Federer, who claimed his 97th singles title with a victory at Rotterdam and regained the world No 1 ranking, becoming the oldest number one in ATP history last month, has made his best-ever start to a season.
"It took a while to get the record", Federer said.
"I don't care what's happening on court, I just try to execute my game", Williams said.
"I got depressed at home for a long while, and I wasn't happy doing the effort to recover my wrist".
"And I got a bit lucky too of course".
"The focus has to be the finals right now". And when I was playing offense he was defending well.
Roger Federer has earned a spot in the semi-finals of the Paribas Open here after beating Hyeon Chung in straight sets.
"I should have lost a match", Federer said.
Each player brought their top game to the last set.
"But for that you need to have a very positive mindset".
Trailing a set and 0-2 in the second, the crowd, including Rod Laver and Pete Sampras, seemingly tried to will better shots out of Federer with loud applause and shouts of encouragement.
Del Potro, nagged by wrist injuries throughout his career, survived three match points before claiming the championship in a third-set tie-breaker, ending a two hour, 42 minute marathon contest. The ball was called out but Coric challenged and after the video review the original call was confirmed.
Despite appearances - at least early on - Federer said he was fine, physically.
There were five breaks in the third.
"I was sort of trying to find a groove".
But Federer's cunning saw him work back into the match in the second set, winning a tiebreak and taking it to a decider.
He brought that same calmness and clarity of goal to his first Masters semi-final, too, while Federer looked a shadow of his 16-winning-streak self.
The match was played under hard conditions with winds swirling around the main stadium.
"For the moment, it's working", Federer said. "Well done. Enjoy the moment", Federer said.
The former US Open victor improved to 16-3 on the season with his 6-2, 6-3 victory over the hard-serving Canadian in just 65 minutes.
Can Del Potro win maiden Masters 1000 title?
The 20-time Grand Slam champion starts the semi-final as favorite, given his 17-match unbeaten run in 2018.Also, he has beaten Del Potro 18 times in their 24 meetings so far. "I was thinking [about missing match points]".
An emotional Juan Martin del Potro could barely believe he had finally won a Masters 1000 series title at the 51st attempt at Indian Wells on Sunday but is determined to keep the trophies coming in his late career renaissance. Yes, he had put together a 35-match streak at the end of 2005, undefeated from Halle through Wimbledon, Cincinnati, the US Open, Davis Cup, Bangkok and into the final of the Masters Cup. "Just three-setters, five-setters the whole way", said Federer. "It's an honor for me to play a final against him". Then, Del Potro was forced to endure wrist surgeries that almost ended his career before it could hit a true prime. "I like it when it's the unknown, even though it can be a bit scary". "But it is not easy".