That's where the similarities to their last run-in ended.
New Zealand's McLaughlin, 29, finally got an opening to surge past Grosjean, took advantage of it and was scarcely challenged the rest of the way to his fourth IndyCar win on Sunday at Barber Motorsports Park.
It was the second time this season they've been in that position, but this time McLaughlin and Grosjean avoided getting tangled up.
Grosjean had been furious with McLaughlin when the two touched heading into a corner at the season opener in St. Petersburg, Florida, both slamming into a tire barrier. McLaughlin drew an avoidable contact penalty.
After winning Sunday, McLaughlin said "there's no hard feelings" between the two. McLaughlin apologized after their previous incident.
"I knew if I hit him this time, it would be bad," McLaughlin said. "I thought we were racing just like we normally do, very clean. It was hard. I knew it was going to be hard passing him. It was just a matter of me biding my time."
Grosjean found himself in his fifth runner-up finish. And while there was a bit of contact -- "We kissed each other a touch," Grosjean said, laughing -- he wasn't worried about McLaughlin getting recklessly aggressive.
"Scott made a mistake in St. Pete, but I know he doesn't race that way," said Grosjean, who planned to fly himself home to Miami after the race. "It was all clean."
McLaughlin wound up with Team Penske's seventh win in 13 races at the permanent road course -- and his first since breaking out with three victories last season. He'd had to catch Grosjean again after getting passed coming out of pit road.
"It's probably the most complete race I've ever driven in IndyCar, from a strategy perspective, picking people off," McLaughlin said. "It was getting pretty tough there in the middle when we were making passes.
"Ultimately, when Grosjean got me out of the pits, he caught me napping. It was a great move by him."
In the end, McLaughlin had the fuel to push the pace more than Grosjean after a three-pit stop strategy. Grosjean pitted twice.
Grosjean started on the pole for the second time this year and led much of the way, but he went wide on Turn 5, leaving McLaughlin enough room to pass on the inside with 19 laps to go. Grosjean was surprised to find he didn't have any push to pass time left to help him overcome the mistake in an otherwise strong weekend.
He wasn't sure whether that was a glitch or "a brain freeze."
The Swiss-born Frenchman and former Formula One driver in search of his first IndyCar victory came close again with his second runner-up finish of the season. He wound up just trying to hold off Will Power, McLaughlin's teammate, a two-time Barber winner who went from 11th to third.
Power and his team pivoted from a two-stop strategy early on, and it worked.
"It worked out well," he said. "We had a very fast car. Any time we had clear air, we were pumping out some seriously fast times. That last sequence was where we gained a ton of track position."
McLaughlin, meanwhile, picked up momentum as the series heads to Indianapolis for May, capped by the Indy 500. He moved up to fourth in series points with four different winners in as many races.
Defending champion Pato O'Ward finished fourth and spent the first part of the race warily keeping an eye on Scott Dixon, who had fumed after contact sent him nose first into a tire barrier at Long Beach.
Series leader Marcus Ericsson, last year's Indy 500 winner, finished 10th in his first race since getting married right after Long Beach.
IndyCar will return to action May 13 on the road course at Indianapolis Motor Speedway. Colton Herta is the defending race winner.
The Associated Press contributed to this report.