Juan Martin del Potro survived three match points before claiming the championship in a third-set tie-breaker.
Juan Martin del Potro is looking for his 22nd career and second straight ATP title in a row after winning earlier this month in Acapulco.
Milos Raonic didn't play in Indian Wells last year because of a string of injuries and surgeries that decimated his season.
World No. 8 Del Potro extended his win streak over the Spaniard to five straight matches, winning 6-4, 7-6 (7/3) at the ATP Tour hardcourt tournament here Tuesday.
South Africa's Kevin Anderson moved one step closer to capturing his second consecutive title.
Del Potro, the 2009 US Open champion and Auckland winner, beat Ferrer 6-4, 6-4 to continue his strong form from the end of last season.
The former US Open champion can take the eighth and final qualification spot for London from Pablo Carreno Busta if he reaches the semi-finals at Bercy, and he will face either John Isner or sixth seed Grigor Dimitrov in the last eight.
Roger Federer's victory boosts his hopes of taking the world number one spot from Rafael Nadal.
Rafael Nadal is chasing a seventh title in a season and a hat-trick of triumphs on the trot, having been crowned US Open and China Open champion in recent weeks.
Rafael Nadal defeated Argentine 24th seed Juan Martin del Potro 4-6, 6-0, 6-3, 6-2 to book a date in Sunday's final against South African 28th seed Kevin Anderson.
World number one Rafael Nadal powered into his 23rd career Grand Slam final on Friday, routing Argentina's 24th-seeded Juan Martin del Potro.
"The way I played or am playing right now, it's not good enough in my opinion to win this tournament," said Roger Federer.
World number Rafael Nadal advanced to the US Open semi-finals on Wednesday by defeating Russian teen Andrey Rublev 6-1, 6-2, 6-2.
Juan Martin del Potro sensationally gatecrashed the US Open again on Wednesday, stunning five-time champion Roger Federer
Argentina 24th seed Del Potro claimed a heroic 1-6, 2-6, 6-1, 7-6 (7/1), 6-4 victory over the sixth-seeded Austrian on a rocking Grandstand court, describing it as night he would remember forever.
World No 1 Scot defeats long-time rival from Argentina in straight sets to reach the last 16 stage in Paris.
World number one Andy Murray set up a French Open blockbuster against Juan Martin del Potro on Thursday, the latest chapter in what has developed into an epic rivalry.
Rome Masters winner Zverev shocked by Fernando Verdasco but world No 1 Murray and former French Open champion Wawrinka advance to the second round.