Fernando Tatis Jr. blasted a go-ahead, two-run homer in the eighth inning, capping the San Diego Padres’ comeback from an eight-run deficit as they stunned the visiting Chicago Cubs 9-8 on Monday.

Jackson Merrill started the San Diego eighth by working a walk from reliever Hector Neris. Neris and closer Adbert Alzolay (1-1) retired the next two hitters before Tatis drilled a hanging slider an estimated 376 feet into the seats in left field for his fourth homer of the year.

The long ball made a winner out of reliever Wandy Peralta (1-0), who pitched a scoreless eighth inning. Robert Suarez worked a 1-2-3 ninth to garner his fourth save of the year, handing Chicago just its second loss in the past eight games.

San Diego got back into the game with a seven-run sixth inning. Jake Cronenworth chased Cubs starter Javier Assad with a two-run homer to right and Ha-Seong Kim reached Jose Cuas for a two-run triple, then scored on Luis Campusano’s groundout. Xander Bogaerts capped the frame with a two-run homer to left off Luke Little.

Assad allowed two runs on three hits and three walks in five-plus innings, whiffing seven. Padres starter Yu Darvish lasted only three innings, permitting four runs on four hits and three walks while striking out four.

Chicago appeared headed for an easy rout through 5 1/2 innings, using a pair of big innings and outstanding pitching from Assad to stifle a San Diego offense that entered the game averaging just 2.5 runs per game over the past six games.

The Cubs got to Darvish for four two-out runs in the second. Ian Happ ripped a single to right with the bases loaded, scoring Nico Hoerner and Mike Tauchman. After Seiya Suzuki re-filled the bases with a walk, Cody Bellinger laced a two-run single that scored Miguel Amaya and Happ.

Another four-run outburst in the fourth made it 8-0. Bellinger lofted a sacrifice fly to left, Christopher Morel followed with an RBI double to left and Dansby Swanson hit a two-run triple to center.