SAN DIEGO — Masyn Winn hit a go-ahead triple past sliding right fielder Nick Castellanos to bring in Jordan Walker with the go-ahead run in the seventh inning, and the Cardinals beat the Padres 2-1 on Thursday night in the opener of a four-game series at Petco Park.

The Cardinals won for the eighth time in 10 games while getting just five hits, but it was enough for Matthew Liberatore (2-1) to get the win after throwing six strong innings.

They also might have gotten a break because Fernando Tatis Jr., a two-time NL Platinum Glove Award winner in right field, was starting at second base for the eighth time this season. Rookie manager Craig Stammen has put Tatis at second to occasionally rest Jake Cronenworth, who is currently on the seven-day IL after experiencing concussion symptoms earlier this week.

Castellanos started in right field instead and couldn’t get to Winn’s line drive, with the ball rolling to the warning track and allowing Walker to score from second. Walker had greeted reliever Bradgley Rodriguez with a leadoff double into the corner in left.

Alec Burleson homered off Padres right-hander Michael King for the Cardinals’ first hit, with one out in the fourth, to tie the game. The left-hander hit a first-pitch changeup 111.2 mph onto the party deck atop the right-field wall.

It was the sixth homer for Burleson, the reigning NL Player of the Week.

Liberatore settled down after allowing three straight baserunners with two outs in the first to fall behind 1-0. He walked Manny Machado and allowed a sharp single to left by Tatis before Xander Bogaerts singled to right on a check-swing blooper to right that fell in just in front of Walker to bring in Machado.

Liberatore picked off Bogaerts to end the inning, then allowed only three baserunners over the rest of his six-inning outing, two of which were erased on double plays. He gave up one run on three hits, struck out six and walked three.