Thairo Estrada hit a three-run homer in the top of the ninth inning to lift the visiting San Francisco Giants to a 7-6 win against the Chicago Cubs in the opener of their three-game series on Monday night.

Giants closer Hector Neris (6-2) started the ninth with a 6-4 lead and retired the leadoff batter, but Jorge Soler reached on catcher’s interference and Mike Yastrzemski walked. Estrada then lifted the first pitch he saw from Neris over the fence in left-center field for a 7-6 lead.

Heliot Ramos and Patrick Bailey also homered for the Giants, who had dropped two of three.

Giants starter Jordan Hicks blanked the Cubs on four hits over five innings, striking out four and walking four.

Camilo Doval pitched the ninth for his 13th save.

Ian Happ hit a three-run homer and Michael Busch had a two-run blast for the Cubs, who have lost four of five.

Cubs starter Javier Assad allowed one run and five hits in five innings. He struck out seven and walked two.

Soler walked with two outs in the fourth before Yastrzemski tripled him home to give the Giants a 1-0 lead.

Nico Hoerner barely beat out a grounder to shortstop with two outs in the sixth and Busch cashed him in by belting the next pitch over the fence in left for a two-run homer and a 2-1 lead.

Ramos homered on the second pitch of the seventh inning to tie it 2-2.

Hayden Wesneski then walked three of the next four batters, bringing Mark Leiter Jr. in from the bullpen. He struck out Yastrzemski but then nicked Estrada with a pitch to force in a run and give San Francisco a 3-2 lead.

The Giants let a high fly on the infield drop with one out in the seventh before Cody Bellinger walked with two outs. Seiya Suzuki then lined an RBI double to left to tie it at 3-3 and bring up Happ, who blasted a three-run homer off Erik Miller (2-2) to give Chicago a 6-3 lead.

Bailey went deep in the eighth to trim the lead to 6-4.