He will play Canada's Denis Shapovalov or Alexander Zverev of Germany in Sunday's final.
The 18-year-old from Richmond Hill, Ont., had his sights set on a place in the top 100 in the ATP rankings this year, but a successful run at the Rogers Cup has guaranteed him a place in the mid-60s - and he's not finished. Should he avenge that loss, Zverev would tie Federer for the most titles this year.
Federer last won the tournament in 2006, since when he has been a beaten finalist on three occasions, and a victory this year would boost his bid to become world number one after next week's Cincinnati Masters.
The youngster responded impressively to Nadal easing through the first set to force a decider, where Shapovalov saved three break points before winning an epic 14-minute third game, which included 10 deuces.
For large spells of the match, the Swiss appeared unusually frustrated, as his first serve dwindled and his much-improved backhand regularly misfired. Never really on a hard court, except at the Hopman Cup. Sometimes you've just got to wait and see how you feel.
"It's what I dreamed of all my life growing up, playing guys like Rafa (Nadal), Roger (Federer), Andy (Murray)", Shapovalov said. "But at the end of the day he did a good job to make me play those points".
However, there was no such reprieve the next time the 12th seed served, with Federer pouncing on his second break-point opening as his opponent fired a forehand wide.
That said, Stephens did win the most recent clash (New Zealand in 2016) and should have a formula in mind to frustrate Wozniacki with a spot in the finals on the line.
The victory marks Wozniacki's first career win against a No.1 and gives the 27-year-old a 6-2 advantage in head-to-head matches with Pliskova. "A bit surprising, to be quite honest, because I hadn't practiced much". "I don't think I played that well in those moments".
Bautista Agut showed great character to break straight back as Federer made just one first serve in the second game, but that was as good as it got for the Spaniard for the rest of the set. Not even I probably achieved finals of a Masters 1000 at that age. Comparing Federer to an elegant freight train, the Canadian said that he had no answers to Federer's transition from baseline to the net.
Meanwhile, Roger Federer continued his pursuit of a third Rogers Cup title, but his first in Montreal.
Donaldson, 20, was seeking a first career quarterfinal in a Masters Series tournament, where he is 0-13 in round of 16 matches.
Taylor Swift assault trial: Judge dismisses DJ's case
During the trial Swift told jurors that Mueller deliberately groped her bottom during a fan meet-and-greet session. She also said that she was doing this as an example for young victims of sexual assault around the world.
Bihar Board Compartmental Result 2017: Know How To Check
As per the scheduled timetable drawn out, the Bihar Board has conducted the 12 class examinations from 1 March to 8 March 2017. The Bihar School Examination Board (BSEB) on Saturday announced intermediate compartmental-cum-special examination results.