SAN FRANCISCO — There were always going to be growing pains for Rafael Devers at first base. Prior to Tuesday, he’d never played the position in the majors or minors. His first two games went smoothly enough, but on Friday night at Oracle Park, the learning curve was on full display.

Devers committed an error along with several miscues in his third career game at first base as the Giants lost 2-1 to the New York Mets, one of which set the stage for New York’s Mark Vientos to hit a go-ahead, two-run double in the sixth.

Robbie Ray took the loss as he allowed two runs over 5 2/3 innings with three walks to three strikeouts.

The Mets loaded the bases with no outs in the top of the fourth, doing so with the help of Devers’ first miscue at first base. With runners on second and third, New York’s Brett Baty hit a slow roller to the infield’s right side. The ball was closer to Ray than Devers, but Devers initially charged the ball hard before reversing to cover first. Devers wasn’t in proper position once Ray fielded the ball and Baty beat out an infield single to load the bases.

Two batters later, Devers avenged the mistake. After Ray struck out Vientos, Devers made a nifty pick to complete an inning-ending 5-3 double play.

Devers’ eventful night was only just beginning. In the top of the fifth, Devers bobbled Brandon Nimmo’s grounder, then kicked the ball around before recovering to grab the ball, step on the base and record the out. Devers laughed at himself as he walked back to the position, but his mood would be less jovial the following frame.

In the top of the sixth, the Mets put runners on first and second with one out. Baty hit a grounder to Devers, who fumbled the exchange as he spun to fire to second base. Instead of getting the force out at second, Devers could only record the sure out at first.

That misplay immediately bit the Giants. With runners on second and third with two outs, Vientos pulled a double into the left-field corner that drove home two runs, gave the Mets a 2-1 lead and knocked Ray out of the ballgame. The following inning, Devers muffed a hard-hit grounder from Juan Soto, his first official error of the night.

With two outs in the bottom of the ninth, the Mets’ Pete Alonso made a leaping catch to rob Patrick Bailey of a game-tying base hit.