The pair played the final last week in Washington, with Zverev winning to claim his fourth title of the season.
Haase outlasted Argentina's Diego Schwartzman 4-6, 6-3, 6-3 in his quarterfinal match.
Nadal, who retained the year-to-date points lead as a result of Federer's loss to Zverev, will take that spot unless Federer plays Cincinnati and gets to the semifinals.
The 36-year-old Swiss had only lost twice in his previous 37 matches but was outfought by the German, who produced a superb display to win in straight sets.
Indeed, with Murray struggling with injuries, Djokovic out for the season and Nadal yet to prove his form on the hard courts, Zverev is conceivably Federer's main challenger for the last major of the year.
Federer then responded to Zverev's cheeky dig in his runner-up speech.
"I've been against the wall a couple times this week and I'm very happy I've come out several times just playing really good tennis in those situations", said Shapovalov after his Friday victory.
"It's what I dreamed of all my life growing up, playing guys like Rafa (Nadal), Roger (Federer), Andy (Murray)", Shapovalov said.
Real Madrid Set For Barcelona Clash In Spanish Cup
The post Spanish Super Cup Won't Be Decided In First Match, Says Pique appeared first on Channels Television . I'm very happy with their confidence in me. "I'm happy for working so well with my staff.
Shapovalov, aged 18 and ranked 143rd, became the youngest player to ever qualify for the semi-finals of a Masters 1000 event as he rallied past Frenchman Adrian Mannarino 2-6, 6-3, 6-4 in front of an excited home crowd.
The win improved Zverev to 5-1 in finals this year with the only defeat coming at the hands of Federer at Halle.
The victory is Zverev's fifth title this year and the second ATP Tour 1000 title.
With Nadal holding the ranking-point edge over Federer and with Nadal entering Cincinnati on several days' rest, the Spaniard has to be considered the favorite to get to No. 1 on August 21st. I had opportunities. But Zverev played extremely well.
Fast forward nine years and the two were back on the Roger's Cup court, but this time as opponents.
Federer was aiming to post a 94th career title which would have moved him into a tie for second with Ivan Lendl, behind Jimmy Connors (109).
"I have reached levels that I never thought I would be able to reach, winning so many titles".
"I wanted to fight a bit more and make the match a bit more tighter", he said. "I don't feel like things are going unnatural".