(Photo credit: David Frerker-Imagn Images)

Fernando Tatis Jr. belted a grand slam and the San Diego Padres kept their hopes of hosting a wild-card series alive with a 7-4 win over the visiting Arizona Diamondbacks on Friday.

The Padres (88-72) are two games behind the Chicago Cubs (90-70) with two games left. San Diego has to sweep Arizona and hope the Cubs lose twice to the St. Louis Cardinals this weekend or else the Padres will have to play the wild-card round in Chicago.

Tatis unloaded in the bottom of the fourth on a 3-2 fastball from Zac Gallen, drilling the pitch into the second deck in left for his 24th homer of the year. The blast capped a five-run inning that included an RBI single from Ryan O'Hearn.

San Diego starter Yu Darvish (5-5) lasted five innings, permitting six hits and two runs with two walks and four strikeouts.

Gallen (13-15) yielded seven hits and six runs, five earned, over 4 1/3 innings. He walked three and fanned three as the Diamondbacks (80-80) were eliminated from playoff contention.

Arizona trailed 6-2 before rallying in the eighth behind the wildness of San Diego relievers Kyle Hart and David Morgan. Hart walked the first two hitters, then got an out before exiting. Morgan recorded the second out before issuing three walks, including bases-loaded passes to Tim Tawa and Ildemaro Vargas, pulling Arizona within 6-4.

Mason Miller then came in from the San Diego bullpen and fanned Jorge Barrosa with a 3-2 fastball to end the inning. The right-hander pitched a scoreless ninth to garner his second save with the Padres and 22nd of the year overall.

The Diamondbacks took an early 2-0 lead behind the long ball. Ketel Marte clouted his 27th homer with one out in the first over the right field wall, and Jake McCarthy added a solo shot to right in the third, his fourth.

However, Tatis' swing erased that advantage and San Diego was able to add on just enough. Jake Cronenworth's bases-loaded walk forced a run in the fifth, and Jackson Merrill ripped an RBI single to right with two outs in the eighth.

Luis Arraez rapped out four hits for the Padres, giving him a 14-game hitting streak.

--Field Level Media