The Home Run Derby will come to Seattle in July as part of Major League Baseball's All-Star Game festivities.
Fans at T-Mobile Park got a sneak preview Friday night.
The teams are scheduled to meet again Saturday when Pirates right-hander Vince Velasquez (4-3, 3.06 ERA) is expected to be activated from the injured list to face Seattle ace Luis Castillo (3-2, 2.97)
The Pirates had just nine homers in May before Friday's outburst. Jack Suwinski went deep twice, with Bryan Reynolds, Ke'Bryan Hayes, Tucupita Marcano, Andrew McCutchen and Carlos Santana also homering
"I would say, of all the games we've played this year, this was probably the best we've executed offensively with our approach," said Pirates manager Derek Shelton, whose club snapped a two-game skid. "We stayed in attack mode.
McCutchen opened the game with the 21st leadoff homer of his career. Santana, who helped the Mariners snap a postseason drought last season dating to 2001, hit a solo shot in the fourth. Suwinski and Hayes went back-to-back in a five-run fifth that broke a 2-all tie
Suwinski added a 445-foot blast to right-center in the seventh, an out before Marcano homered.
"Some of us were just laughing to each other just because the game plan we had going in wasn't to slug the whole game the way we did," Suwinski said.
Reynolds capped the home run derby with a solo shot in the eighth. He finished 3-for-4 with four RBIs.
"We were just locked in, putting the barrel on the ball, driving the ball," Reynolds said. "It doesn't happen every day, so it was nice that we were able to feed off each other."
Seattle starter George Kirby, who had allowed just three homers through his first nine starts of the season, was taken deep four times.
"Very uncharacteristic of our pitching," Mariners manager Scott Servais said. "They came out swinging it and certainly have some power in the middle of their lineup. ... With the warm weather, the ball is carrying better, but we left too many balls up to a team that hits the high fastball.
Julio Rodriguez and J.P. Crawford homered for Seattle. Rodriguez, who has been struggling, also hit a two-run single.
"You're starting to see Julio -- his timing is so much better," Servais said. "Lot of good signs from him."
The Mariners got a scare when Ty France was hit in the bill of his batting helmet by a Mitch Keller pitch in the fifth inning. France was plunked in the left hand Tuesday against Oakland and sat out a game, but he responded with two homers Thursday
Velasquez, who has been sidelined by right-shoulder inflammation, will make his eighth start of the season Saturday but his first since throwing just three innings against Tampa Bay on May 4. He's 0-0 with a 2.84 ERA in four career appearances against Seattle, including two starts.
Castillo threw six shutout innings in his last start against Oakland, allowing four hits and striking out eight, after struggling for most of the month. The right-hander is 5-4 with a 2.51 ERA in 13 career starts against Pittsburgh.
--Field Level Media