Novak Djokovic and Juan Martin del Potro will put their close friendship aside on Friday when they clash for a place in the French Open last 16, the tournament's biggest match-up so far.
Djokovic is the overwhelming favourite not just to see off the giant 1.98m Argentine, but also go on to take the title off Rafael Nadal and assume the world number one spot.
His form makes him easily the hottest player on tour.
The Australian Open champion, who has also won all four Masters titles in 2011, now stands five wins away from equalling Guillermo Vilas's record for a winning streak.
The Serb is also only three away from John McEnroe's 1984 record for an undefeated start to a season.
But win or lose on Friday, the 24-year-old Djokovic insists nothing will break his friendship with the injury-plagued Del Potro.
"He's a great guy. We have a really friendly relationship off the court, and regardless of what happens, we'll still stay friends," said Djokovic.
"But we're both professional. We want to win on the court.
"He has always had the quality to be at the top of the men's game... he's a top player for me."
Argentine 25th seed Del Potro, the former US Open champion and a 2009 semi-finalist in Paris, made the last 32 with a 6-3, 6-2, 6-4 win over Slovenia's Blaz Kavcic.
Del Potro missed last year's Roland Garros to recover from wrist surgery and was almost forced out of this edition because of a hip injury picked up in Madrid, which forced him to scratch from his clash with Nadal.
The former world number four's ranking slipped to 485 during his time off tour, but he has been in fine form in 2011, winning tournaments at Delray Beach and Estoril.
"I'm trying to improve my movement on court, and build physically and mentally because the way you feel in your head is very important in tennis, and I want to be on the same footing as all the others," said the 22-year-old.
"Once you have been injured, it's a bit difficult to feel you're back at the same level as before."
Djokovic has won all of the pair's three previous meetings without dropping a a set.
The two are close friends off court, and while Del Potro is determined to do his utmost to bring his pal's 41-match winning streak to an end on Friday, he says his full recovery from injury remains his main priority.
"It's a long road. You never want to lose sight of your main objective, which is to be well-prepared all year," said Del Potro, whose best win streak was 23 in 2008.
"I don't know if many players have had a comeback like mine, but I try and be calm. I try and improve. I try and play better than in 2009. I'm just happy, because I can play tennis and this is what I like most."
Even with seven million dollars in prize money safely banked away, the Argentine will not be tempted to have a friendly wager with his Serb rival.
"Of course not. He's much richer than I am," he said.