Apr 12, 2022; San Francisco, California, USA; San Francisco Giants assistant coach Alyssa Nakken (92), the first female to coach on the field at first base, during the third inning against the San Diego Padres at Oracle Park. Photo: IC

Brandon Belt hit the fifth pitch of the bottom of the first inning for a two-run homer, Alex Cobb won his San Francisco Giants debut and the reigning National League West champs bombed Yu Darvish en route to an 13-2 romp over the visiting San Diego Padres on Tuesday.

Giants coach Alyssa Nakken also made history in the game.

Nakken, who serves as a general assistant alongside manager Gabe Kapler on the San Francisco bench, became the first woman to coach on a Major League Baseball field in a regular-season game when she replaced ejected Antoan Richardson as the Giants came to plate in the bottom of the third inning.

Nakken, who had been a base coach during spring training, was immediately congratulated by Padres first baseman Eric Hosmer, who shook her hand.

The Giants led 10-1 at the time, having sent Darvish (0-1) to the showers with a six-run first and a four-run second.

Belt's homer, his second of the season, came after Mike Yastrzemski led off with a single off Darvish, who had thrown six no-hit innings in his season debut against the Arizona Diamondbacks on Thursday.

Thairo Estrada added a two-RBI single, Steven Duggar a sacrifice fly and Joey Bart an RBI single to complete the six-run uprising.

After a Wil Myers' run-scoring double got the Padres on the board in the top of the second, the Giants ended Darvish's night when Wilmer Flores singled home the second run of the second, increasing the lead to 8-1.

When Estrada added an RBI double and Duggar an RBI single off Padres reliever Nabil Crismatt, the book was closed on Darvish's night. The right-hander was charged with nine runs on eight hits and two walks in 1 2/3 innings. He struck out two.

Only once has Darvish yielded more runs, when the Miami Marlins put up 10 against him on July 26, 2017, when he was pitching for the Texas Rangers.

Cobb (1-0), signed as a free agent over the winter, coasted through five innings, striking out 10. He allowed two runs on four hits and two walks.

The Giants tacked on a run in the fifth on a double by Yastrzemski, then teed off on ­Myers, summoned in from right field, when Joc Pederson and Flores homered within a three-batter stretch in the eighth. The homers, both solo shots, were the first of the season for both players.

Flores finished with three hits, while Yastrzemski, Belt, Estrada, Pederson and Bart collected two apiece for the Giants, who had totaled just 12 runs in their first four games.

Myers finished with two hits for the Padres, whose second run was the product of an ­Austin Nola infield out in the fifth.