Here's what went on.
Haase will face the victor between second-seeded Roger Federer and Roberto Bautista Agut in the semifinals on Saturday.
Roger Federer overcame a weak first set to post a 4-6, 6-4, 6-2 victory over Spaniard David Ferrer in an earlier third-round match.
Federer took the opening with both hands as he ruthlessly served out the set in the next game easily, clinching it 6-4.
The 36-year-old Federer blasted nine aces and lost just nine points on his serve as he extended his match win streak to 16 - his longest win streak in five years.
Shapovalov battled back after Nadal cruised through the first set, then erased a 3-0 deficit in the tiebreaker for the biggest victory of his career. I played in five finals this year.
The Swiss maestro, who recently clinched his 19th Grand Slam title at Wimbledon, eased past Bautista Agut 6-4, 6-4 in a one-sided quarter-final clash that lasted one hour and eight minutes. Federer was broken once in the first set but in the second won 28 of 31 points on his service.
Federer's defeat of Bautista Agut was his seventh in a row without a defeat - or loss of a set - in the series with the Spaniard.
Next up is Roger Federer who served his way into his 6th final of the season besting Robin Haase 6-3, 7-6 (5).
Alexander Zverev ended a dream week for 18-year-old Canadian Denis Shapovalov with a 6-4, 7-5 victory in the semifinals of the Rogers Cup on Saturday night.
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.
The first set was a disaster for Shapovalov. But Mannarino got that one back in the next game.
Earlier, Haase recovered to defeat Argentine Diego Schwartzman 4-6 6-3 6-3 in their quarter-final.
Having performed so admirably to force a tie-break, Haase started slowly but again showed his character by winning four points in a row from 4-1 down. In the victory, Haase won 84 percent of his first serve points and 31 percent of his second serve points. "At the end that's what matters because I spent hours and hours on the practice courts in the past year".
However, it will be an uphill task for Haase in the semi-final, given Federer commanding display at the hard court tournament so far.
Ferrer had also come through two tough matches at this event, beating Britain's Kyle Edmund and world number 17 Jack Sock, and he applied immediate pressure on Federer from the off.