Pete Alonso — who nearly left New York as a free agent over the winter — homered in his first home at-bat of the season to power the Mets to a 5-0 win over the Toronto Blue Jays on Friday afternoon.The Mets improved to 42-22 all-time in home openers, including 12-5 since Citi Field opened in 2009. The Blue Jays had their four-game winning streak snapped.Alonso appeared likely to leave the Mets at multiple points during the offseason — especially on Jan. 25, when owner Steve Cohen called the negotiations “exhausting” and “worse” than the ones with free agent Juan Soto, who signed a 15-year deal worth $765 million in December.But Alonso and the team agreed on Feb. 12 to a two-year deal worth $54 million with an opt-out following this season. On Friday, Alonso received a thunderous ovation during pregame introductions before he hit a two-run blast just beyond the right field wall off Kevin Gausman (1-1) in the first inning.Alonso, whose 229 homers are 23 shy of Darryl Strawberry’s franchise record, emerged from the dugout for a curtain call and raised his arms to the sellout crowd of 43,945.Alonso also factored into the Mets’ three-run sixth against a trio of Blue Jays pitchers. After Francisco Lindor walked to chase Gausman, Soto ripped an RBI double against Mason Fluharty and Alonso was intentionally walked before Brandon Nimmo added another run-scoring double. Starling Marte followed by lofting a sacrifice fly off Jacob Barnes.