Last year, he came to Paris having won 21 consecutive matches at Grand Slam tournaments.
And in 2013? Well, Djokovic arrived having lost two of his preceding four matches, both on clay. The man responsible for one of those surprising defeats, Bulgaria's Grigor Dimitrov, just so happens to be Djokovic's next opponent at Roland Garros.
"It's going to be a tough one for both of us, definitely," Djokovic said, looking ahead to their third-round match. "I need to be on top of my game."
Ranked and seeded No. 1 at the French Open as he tries to complete a career Grand Slam, Djokovic hasn't faced much difficulty so far, winning both of his matches in straight sets, including 6-2, 6-0, 6-2 against 83rd-ranked Guido Pella of Argentina on Thursday.
Truth is, the most vexing thing for the Serb — and many other players — on Day 5 of the clay-court major was the wet weather. Djokovic gestured at the dark, threatening sky between points, as if to say, "Please don't rain again. Let me finish my work first!"
"The most important thing for a player in these interruptions and rain delays is not to get frustrated mentally," Djokovic said, "because it's a very fine line. ... Your intensity is there, and suddenly they call it off."
Because of repeated rain, only 18 of Thursday's 32 scheduled singles matches were completed. Six were suspended in progress — defending champion Maria Sharapova led Canada's Eugenie Bouchard by a set and a break when they stopped — and eight were postponed entirely, including seven-time French Open winner Rafael Nadal against Slovakia's Martin Klizan.
All of which created quite a crammed slate for Friday.
In addition to Sharapova resuming her match, and Nadal starting his, others due on court included 17-time major champion Roger Federer against No. 30 Julien Benneteau; No. 12 Tommy Haas, who is 35, against 20-year-old American qualifier Jack Sock; No. 15 Gilles Simon of France against No. 18 Sam Querrey of the United States; No. 19 John Isner against 21-year-old Ryan Harrison in an all-U.S. matchup; and 2008 champion Ana Ivanovic against Virginie Razzano, the Frenchwoman who stunned Serena Williams in the first round last year.
If things go to plan, Djokovic and Dimitrov would meet Saturday, 3 1/2 weeks after their last match. That was in the second round of the Madrid Open, where the 21-year-old Dimitrov emerged with a 7-6 (6), 6-7 (8), 6-3 victory.
Dimitrov is seeded 26th at the French Open and reached the third round at a Grand Slam tournament for the first time. His first-round opponent, Alejandro Falla, retired while trailing early in the second set because of stomach problems, and Dimitrov defeated Lucas Pouille of France 6-1, 7-6 (4), 6-1 Thursday.
"I'm actually really looking forward to the next round," said Dimitrov, who's been learning how to deal with the paparazzi since being linked to Sharapova. "I mean, hopefully it's going to bring out the best of me."
While success at this level is still pretty new for Dimitrov, Djokovic has won six major titles, including the Australian Open in January. Djokovic has yet to win the trophy in Paris, though: He lost to Federer in the 2011 semifinals, and to Nadal in last year's final, and says the French Open is his top priority this season.
Both Djokovic and Dimitrov know that one has a big advantage when it comes to experience in big matches — and in best-of-five-set matches.
"It's going to be very physical," Djokovic said. "All the hard work that I put into preparations for this tournament hopefully will play to my advantage and will pay off on the court."
For the second day in a row at Roland Garros, no seeded men lost Thursday. But there were some unexpectedly early departures among the women, none more so than by 2011 champion Li Na, who was seeded sixth.
Li, who also twice was the runner-up at the Australian Open, lost 5-7, 6-3, 6-2 to 67th-ranked American Bethanie Mattek-Sands.
By earning her fourth career win in 25 tries against top-10 players, Mattek-Sands helped give the United States five women in the third round at the French Open, the country's most since six made it in 2004. That's also the most that far at any Grand Slam tournament since the half-dozen at Wimbledon in 2005.
"We have a lot of talented, young kids," the 28-year-old Mattek-Sands said, then added with a wink and a smile, "Obviously, older kids, too."
The other Americans who won Thursday were No. 17 Sloane Stephens and 54th-ranked Jamie Hampton.
Up next for the 23-year-old Hampton is No. 7 Petra Kvitova, the 2011 Wimbledon champion. The 20-year-old Stephens, meanwhile, faces 92nd-ranked Marina Erakovic, who beat No. 16 Dominika Cibulkova 6-2, 2-6, 6-4 to become the first woman from New Zealand to reach the French Open's third round.
Like other players Thursday, Stephens waited and waited and waited through rain delays before wrapping up a 6-1, 6-3 win against Vania King of the U.S.
"You literally have nothing to do," Stephens said. "Should I eat? Do cartwheels?"
Follow Howard Fendrich on Twitter at http://twitter.com/HowardFendrich