The 18-year-old Canadian fought off exhaustion and held her nerve to triumph 6-4, 3-6, 6-4 over the three-time grand-slam champion, becoming the first wildcard victor of the prestigious event.
Her most dominant win during the 12-day tournament came in the quarterfinals, a 6-0, 6-1 rout of two-time major champion Garbine Muguruza.
The 22-year-old Bencic was the teenager star who won the position of number seven in a world but unfortunately her career was stalled after back and wrist injuries.
Raonic beat the 19-year-old Serb 6-3, 6-4 on Thursday to reach the semi-finals and improve his record to 19 wins and just four defeats at Indian Wells since 2014.
Game on, indeed. The second set began frantically, with three breaks of serve in the opening four games.
"I just tried to play consistent, be aggressive when I had the first chance". She broke Williams in the match's longest game that went to deuce five times when Williams' forehand went wide.
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Thiem is through to the semi-finals at Indian Wells for the first time, having reached the quarters once before in 2017. I think that's what's happening with me right now. Andreescu's returning was very strong as she broke Svitolina's serve on 6 occasions. "She's here as a wild card, and she beat a lot of good players", Kerber said.
"I think you definitely need it against the top of the world, to be just incredibly fit, and not just one week but many weeks in a row".
She had to fight for the lone break of the second set as Williams saved four break points to hold for 2-2 and saved four more in the sixth game before Kerber finally converted one for a 4-2 lead that would stand up the rest of the way.
Andreescu bounced back, putting away a smash to set up her fourth match point before Kerber's backhand error ended it after 2 hours and 18 minutes. When Andreescu was broken by Kerber early in the deciding set it seemed her remarkable week looked set to end in disappointment.
Pliskova raced to 4-1 lead before wrapping up the second set. "And now to be able to have my name in front of so many fantastic champions is, it means the world to me", said Andreescu. "But I have had many moments like this in the past, playing Challenger events, juniors".
"I was really trying in the first set especially to find my rhythm but it was not so easy". She won her third career title at Dubai last month and her first since 2015. "Another goal of mine was to make history, and I just did".