SAN DIEGO (Interstat) — Fernando Tatis Jr. crushed a walk-off home run with two outs in the bottom of the ninth inning Wednesday afternoon, lifting the San Diego Padres to a 5-4 victory over the Cincinnati Reds at PETCO Park before 37,393 fans.

The game lasted 2 hours, 37 minutes.

Tatis, who finished 2 for 5 with a home run and two RBIs, sent a 1-0 pitch from Reds reliever Tony Santillan over the left-field wall for his second homer of the season. The blast capped a wild eighth inning that saw both teams trade blows, and it gave the Padres a series win after they dropped the opener 5-3 on Tuesday.

San Diego improved to 35-32, while Cincinnati fell to 32-35.

The teams traded early runs but the Reds appeared in control after building a 4-2 lead on solo home runs in the seventh and eighth innings. JJ Bleday led off the seventh with his 11th homer of the season, a solo shot to right off Padres starter Michael King. Eugenio Suarez added a solo homer in the eighth, his fifth of the year, to push the Reds’ lead to 4-2.

But the Padres answered in the bottom of the eighth. Jackson Merrill led off with a double off Reds reliever Zach Maxwell. Gavin Sheets followed with an RBI double, scoring Merrill to trim the lead to 4-3. After an out, Samad Taylor singled to center field, driving in pinch-runner Jase Bowen to tie the game 4-4.

Neither team scored in the top of the ninth. The Reds put a runner on base when Matt McLain singled off Padres reliever Ron Marinaccio, but a double play erased him. Sal Stewart walked, but Spencer Steer grounded into a forceout to end the inning.

In the bottom of the ninth, Santillan retired Rodolfo Duran on a groundout and got Sung-Mun Song to ground out. Tatis then connected on the 1-0 pitch for the game-winning home run.

Wandy Peralta, who pitched a scoreless top of the ninth, earned the win, his first of the season against no losses. Chase Petty took the loss, also his first decision of the year.

Cincinnati starter Brady Singer delivered a solid outing, allowing two earned runs on six hits over six innings with five strikeouts. King worked 6 2/3 innings for San Diego, giving up three earned runs on seven hits while striking out three.

Spence Steer put the Reds ahead 2-1 in the fourth inning when he hit a two-run home run, his 10th of the season, after Bleday had walked. That gave Cincinnati a 2-1 lead, and the Reds extended it to 3-1 in the seventh on Bleday’s homer.

San Diego struck first in the bottom of the first. Jackson Merrill singled, and Manny Machado doubled him home for a 1-0 lead. The Reds tied it in the fourth on Steer’s homer, then took the lead for good until the late Padres rally.

Cincinnati outhit the Padres 10-8 through seven innings, but San Diego finished with 11 hits to the Reds’ 10.

The Reds are now 1-2 on their four-game West Coast trip. They host the Arizona Diamondbacks on Friday to begin a 10-game homestand. The Padres travel to Baltimore for a three-game series starting Friday.

Interstat’s game simulator had projected a final score of San Diego 3, Cincinnati 2. Interstat’s ELO system gave San Diego a 59.80 percent probability to win. The Padres were installed as a pregame favorite with a spread of minus 1.5. The total of nine runs went under the over/under line of eight.