Djokovic defeated Nadal on clay for the first time in 10 tries, beating the top-ranked Spaniard 7-5, 6-4 in the final of the Madrid Open, to extend his unbeaten start to the season to 32 matches.
The second-ranked Djokovic squandered a 4-0 lead in the first set, but recovered to end Nadal's latest winning streak on clay at 37 matches and earn the Serb his third straight victory over Nadal in finals this season.
Djokovic's sixth title of 2011 allowed him to surpass Bjorn Borg's 31-match season-opening run in 1980. He trails only John McEnroe's 42-0 start in 1984.
"Probably it's right at the top," Djokovic said about beating Nadal on clay on Spanish soil. "Under the circumstances I was playing an unbelievable match. ... I stepped onto the court today believing I could win. I needed to be aggressive and it was a great match."
Djokovic's run of 34 straight wins since Serbia's Davis Cup triumph in December is the eighth best of all time.
"I came up against a great player obviously -- he's having a monster year," Nadal said. "He was better, you have to accept that."
He also lost to Djokovic in the finals at Miami and Indian Wells this year.
Nadal's last defeat on clay came nearly two years ago against Robin Soderling at the French Open. He had won six titles on clay since, and this was only his seventh loss on the surface in 196 matches dating to 2005.
Nadal had split the last two finals here with Roger Federer, and beat the Swiss star in three sets in the semifinals on Saturday. But Djokovic proved too tough and avenged his 2009 loss to Nadal at the Magic Box arena, when the pair squared off in a record 4-hour plus semifinal.
Djokovic spent most of the past few seasons as the No. 3 player in the world behind Nadal and Federer, but started the year by winning the Australian Open and hasn't looked back.
On Sunday, he was faced with what is widely considered the toughest test in tennis -- Nadal on clay -- and his victory is yet another signal that a permanent power shift may be in the works.
"I'm happy I can play the best tennis when I needed to and maybe that was lacking a lot in the past," Djokovic said. "Maybe that's what was missing against Rafa and Roger in the past tournaments."
Djokovic raced out to a 4-0 lead after Nadal netted to be broken for the second time.
"The game started terribly," said Nadal, who also won here in 2005. "I have to play more aggressive with the forehand."
The Spaniard broke back immediately and then pulled to within 5-4 after converting his second break point with a shot into the corner.
Nadal then saved three straight set points to even it before Djokovic took the set on his fourth try when his backhand took a lucky bounce on the net cord and left Nadal no chance.
In a match full of great shots, Nadal fired up the crowd with a spectacular between-the-legs lob to set up three break points in the first game of the second set. Nadal slammed a forehand down the line to break, but the stubborn Djokovic bounced right back to level in the next game.
"Every point took an average 10-15 rallies. I needed to work hard for my points," Djokovic said.
Djokovic's crosscourt backhand troubled Nadal throughout and it set up three straight match points and Djokovic converted the second when Nadal sliced a backhand wide after a long rally.
The Serb earned $849,000 for the victory.
While Nadal holds a healthy advantage over Djokovic in the world rankings, the Spaniard said it's only a matter of time before Djokovic takes over the No. 1 spot if he keeps playing like this.
"The No. 1 ranking is not in danger -- it's finished. Let's not lie to ourselves, that's the reality," Nadal said. "Nobody likes to lose. I have to see what's missing and working with a cool, open mind to decipher things and find the solutions. To try to do a little better next time."
Djokovic tried to quell expectations -- especially with the French Open coming up on May 17.
"If I want to reach No. 1 I will have to play consistently well because that's what Rafa and the other players will do," he said. "Probably because of my winning streak and being in the shape of a lifetime -- I'm playing the best tennis of my career -- I'm probably one of the favorites [at Roland Garros]."
The 18th-ranked Kvitova won the first set tiebreaker when Azarenka shot long, and secured her first Masters series trophy when Azarenka returned long on the first championship point.
Azarenka only managed to convert three of nine break chances as Kvitova defended her serve well despite a shaky service game.
"I was very nervous and perhaps that was the problem," said Kvitova, who will be the sixth Czech player to reach the top-10 when she jumps to No. 10 in the WTA rankings coming out Monday. "I think it's the best tennis that I've played. I was very offensive."
Azarenka hit only 10 winners to go along with her 21 unforced errors. Perhaps sensing the missed opportunity, she broke into tears after the loss.
"She played great this week, [she] deserved it," said the Belarusian, who will jump one spot to a career high of fourth in the rankings on Monday despite coming up short in her bid for a third title this season.