Juan Soto blew out the candles on Bob Melvin's three-day homecoming party with an eighth-inning grand slam Sunday afternoon, propelling the visiting San Diego Padres to a 10-1 victory of the Oakland Athletics and a three-game sweep of their interleague series.

Soto also belted a two-run homer an inning earlier to finish 3-for-5 with six RBIs in the Padres' season-best fourth straight win. The grand slam was the first of his career and the two homers gave him 32 for the season, while the career-high six RBIs boosted his total to 98.

Nick Martinez and Pedro Avila both played roles in San Diego's run-away, each allowing just one hit in three innings with five strikeouts. Avila (2-2), who pitched the fourth through six innings, was credited with the win.

Before Soto's power display, the Padres scored twice apiece in the fourth and sixth innings, all after A's right-hander Joe Boyle had impressed in his big-league debut, shutting out San Diego over the first three innings on just one hit. He walked two and struck out four.

Luis Campusano and Eguy Rosario had RBI singles to open San Diego's scoring off Ken Waldichuk (3-8) in the fourth, before Matthew Batten delivered a two-run single in the sixth.

Soto's homer in the seventh followed a single by Fernando Tatis Jr., while his grand slam came after a Jose Azocar hit by pitch, a Batten single and a Jurickson Profar walk.

The A's (46-103) avoided a shutout in the last of the eighth when Brent Rooker bombed his 26th home run of the season off the Padres' fourth pitcher, Ray Kerr.

Rooker finished with two of Oakland's six hits.

Xander Bogaerts had two hits and scored twice for the Padres, while Campusano, Batten and Manny Machado also contributed two hits apiece to a 13-hit attack.

In completing a 6-3 trip, the Padres (72-78) outscored the A's 23-6 in Melvin's first return to Oakland since an 11-year stint as the A's manager.

--Field Level Media