For 31 laps, the Azerbaijan Grand Prix was not a classic.
Max Verstappen moved his way to the front of the pack from third on the grid in the opening 12 laps, while Lewis Hamilton moved in the opposite direction at the pit stops between Laps 11 and 13. But just as the positions looked locked in for the final 20 laps, the left rear tyre on Lance Stroll's car deflated at 200 mph and all hell broke loose.
What followed created one of the most remarkable finishes to a Formula One race in recent memory. Here's how it went down.
Stroll experienced a tyre failure on the long pit straight that pitched his Aston Martin hard left into the barriers.
Thankfully, Stroll emerged unharmed from the wreckage, but was understandably shook up.
What Stroll said: "I am frustrated not to finish the race, but I am OK. I am not sure what happened to cause me to spin on the straight because there was no sign of any issues, so we need to investigate."
What Pirelli's Mario Isola said: "The preliminary investigation is that it is probably due to an external factor or debris, kerb, or whatever, but I don't want to jump to a conclusion now as the plan now is to make a thorough investigation and make a report to the teams and the FIA that will be hopefully before Paul Ricard. Obviously it is a priority."
The pit lane was closed during the resulting Safety Car period, meaning the advantage of diving into the pits was lost when it reopened one lap before racing resumed on Lap 35.
The only real winner was Stroll's Aston Martin teammate, Sebastian Vettel, who had briefly led the race and pitted later than his rivals, meaning he had fresher tyres to attack the cars in front.
Vettel was sixth at the restart but moved up to fourth in the following two laps, passing Charles Leclerc and Pierre Gasly. The moves were key to his second place finish, which was handed to him on a silver platter when events unfolded the way they did later in the race.
What Vettel said: "Let's be honest, we obviously had fresher tyres that helped with warming up and switch on, so a great day and I'm over the moon. It's a great podium and we didn't expect that when we came here but even on Friday, even though we were nowhere, I was feeling quite relaxed. Yesterday we didn't quite get it but today we did."
In the laps leading up to Verstappen's tyre failure, he, Perez and Hamilton were trading fastest laps in the fight for second position.
Perez went first with a 1:44.794 on Lap 43. Hamilton followed up with a 1:44.769 on the same lap. Verstappen blew them both away with a 1:44.481 on Lap 44.
There is no indication these fast laps contributed to Verstappen's failure, but they show how hard the drivers were pushing in that moment. Verstappen's time was unbeaten on the final lap when all drivers had fresh tyres back on their cars after the restart.
Max Verstappen's left-rear tyre failed at the end of the lap, leaving him helpless to stop his car spinning into the wall running opposite the pit lane.
Verstappen, who was cleared after a precautionary trip to the medical centre, confirmed the failure came out of nowhere.
What Verstappen said: "I didn't feel anything up until the moment that I suddenly went to the right. The tyre just blew off the rim.
"It's not a nice impact to have. It's quite a dangerous place to have a tyre blow out at that speed. But all fine with me, the car not so much."
"We were fully in control. Of course, it's very disappointing what happened. We lost out on a lot of points, we could have opened up that gap in the championship as well, so to have this happening, especially so close to the end, is very frustrating."
Red Bull's sporting director Jonathan Wheatley quickly radioed FIA race director Michael Masi to say there had been no warning whatsoever that a failure was imminent, before suggesting he red flag the race to prevent similar failures on other cars.
The FIA agreed and red-flagged the race. It was later confirmed it would resume with a standing restart, effectively confirming a two-lap sprint to the finish.
Red flag delay
Under F1's rules, teams were allowed to change tyres while they waited for Verstappen's car to be cleared and for the race to resume.
This was further great news for Vettel, who had a completely fresh set of soft tyres to hand which would give him ideal grip off the line at the start.
As the cars lined up at the end of the pit-lane, Hamilton was trying to think about the bigger picture of his championship fight with Verstappen, telling Mercedes the season is a "marathon, not a sprint" and that they should weigh up risk/reward accordingly.
One car further down the pit-lane, Red Bull feared its other car -- now leading the race -- would not make the finish.
After the race Christian Horner revealed the team fired up Perez's engine at the last possible moment as the Mexican driver's car had been losing hydraulic pressure in the second half of the race.
The race was restarted with the remaining drivers in the race forming up on the grid. As he waited for the lights to go out on the second grid slot, Hamilton's brakes were noticeably smoking as they overheated.
Hamilton got a better jump off the line compared to Perez, but he quickly went straight on at Turn 1.
It was later revealed he had inadvertently hit a switch related to his car's brakes.
The "magic" brake setting is used by Mercedes to regulate brake temperature during formation laps and while under the Safety Car, when the pace is much slower than normal. It is supposed to be switched off when returning to racing speed.
What Hamilton said: "On that restart I think when Checo moved over towards me I clipped a switch. It basically switches the brakes off, so I just went straight. I had no idea that I'd even touched it.
"It's very hard to take. But I'm mostly just really sorry to the men and women in the team who've worked so hard for these points. We will regroup and come back stronger."
Hamilton went straight on at Turn 1, meaning an extra podium position was up for grabs.
Vettel had used his improved grip off the line to hold second, while Pierre Gasly was desperately holding on to third position ahead of the charging Ferrari of Charles Leclerc.
With Vettel comfortable in second position, attention turned to the fight for the final spot on the podium.
Thanks to being inside DRS range at the end of the penultimate lap, Leclerc caught and briefly passed Gasly on the main straight.
However, Gasly defended brilliantly, positioning his car on the inside of the circuit to reclaim third position at Turn 1. Leclerc tried again at Turn 2 and Turn 4 but Gasly refused to yield.
What Gasly said: "Especially in the last two laps, I knew I would be in a tricky position to defend my position on Charles right behind and that's exactly what's happened.
"All the straights he was right there. He actually passed me before Turn 1... I saw the podium, like right in front of my eyes, and I just gave everything I could. In the end I made it possible. It was an intense battle but exactly how I like racing. Was very hard but fair and yes I am really pleased for the guys to get this podium together."
Gasly's superb defensive work put Leclerc on the back foot, and he was soon defending fourth position from McLaren's Lando Norris, but held on through the middle sector.
Although the final two laps looked fairly routine for Perez out in front, he said he had feared a late retirement due to the hydraulic issue.
What Perez said: "First of all I have to say I'm very sorry for Max because he did a tremendous race, and he really deserved that the win.
"It would have been incredible to get that one-two for the team. But at the end, you know it is a fantastic day for us.
"We were close to retiring the car, but luckily we managed to finish the race. And really, it was quite difficult all the way until the end."
At the back of the field, there was nearly further drama, with Haas driver Nikita Mazepin nearly causing a massive accident with teammate Mick Schumacher.
Schumacher had reeled Mazepin in down the back straight but the Russian driver left it late to move to the right. Schumacher avoided contact and finished the race just fractionally ahead, but he was not happy.
On the radio afterwards, a furious Schumacher said: "What the f--- was that? Honestly, does he want to kill us?"
The last lap incident between Schumacher and Mazepin 😳 pic.twitter.com/VjTsbRyUq1— ESPN F1 (@ESPNF1) June 6, 2021
The result means the gap in points between Verstappen and Hamilton remains unchanged in the drivers' standings at four points after six races.
In the constructors' standings, Red Bull has extended its gap to 26 points over Mercedes thanks to Perez's win and Valtteri Bottas' failure to feature in the points.
In both camps there was a sense of "what if?", but undoubtedly Mercedes leaves Baku feeling more bruised by the result.
What Mercedes boss Toto Wolff said: "It just feels painful. You can say we had we had the hand almost close to the trophy because Max didn't score, but I don't know, it's just the emotion, the frustration is just so overwhelming at the moment.
"I don't know if I would have rather taken third or this result. I can't even tell you.
"What I take away is that we must bring our A-game to fight for this championship and our car was not there all weekend.
"Operationally, we just need to perform faultlessly. And all of us haven't done that the last two weekends."
What Red Bull boss Christian Horner said: "Baku has been a Mercedes stronghold for several years now, so we expected it to be very tight with them, and to have both cars running ahead in the race was more than we could have hoped for coming into the weekend.
"It's frustrating not to get the one-two. It would have been our first since 2016 when we've done everything right.
"Having lost Max, it was a big roller coaster of emotions because Sergio was losing hydraulic pressure and it was marginal whether he would get to the end of the race.
"Then they red flagged the race and part of me just wanted the race to be declared as a result there and then, because when we had the restart the only thing that could change was that we lose the race and give a chunk of points back to Lewis.
"As it turned out, I'm glad they did do the restart. Checo's hydraulic pressure stayed intact, Lewis made a mistake at Turn 1 and we got the race win and Max leaves here in exactly the same position that he arrived, and we have extended our lead in the constructors'."