SAN DIEGO -- There are few hitters the Giants would rather have at the plate with the game on the line than LaMonte Wade Jr.

Wade added to his growing list of ninth-inning heroics by delivering a go-ahead RBI single off Mark Melancon to lift the Giants to a dramatic 6-5 comeback win over the Padres in Tuesday night’s series opener at Petco Park.

• Box score

With the win, the Giants maintained their perch atop the National League West standings, holding off the lurking Dodgers, who beat the Rockies, 5-4, in 10 innings on Tuesday.

• Games remaining: 11
• Standings update: One game ahead of the Dodgers for first place in the NL West
• Magic number for division title: 11

The Giants and Padres were tied, 5-5, entering the ninth, but San Francisco rallied behind three consecutive one-out singles by Brandon Belt, Buster Posey and Wade, who is now 12-for-19 (.632) with a 1.597 OPS and 11 RBIs in the ninth inning this year. Wade managed to bloop a 1-2 curveball from Melancon to shallow left field, allowing Belt to score from second and put the Giants ahead, 6-5.

“LaMonte was in battle mode,” manager Gabe Kapler said. “He’s been so big in those situations. He got a ball that he was able to fight off and kept us alive and put us in a good position.”

After spurring ninth-inning comebacks against the Dodgers, D-backs, Rockies and A’s this year, Wade has officially earned the nickname “Late Night LaMonte” from his Giants teammates.

“Hopefully it can be Early Game LaMonte at some point,” Wade said. “But if it’s going to be Late Night, it’s Late Night.”

Tyler Rogers took the mound in the bottom of the ninth, but the Padres didn’t go quietly. Wil Myers reached on a fielding error by Brandon Crawford and Jake Cronenworth singled to put a pair of runners on for Manny Machado, who crushed two home runs earlier in the night. Machado hit a 112.2 mph missile to the right side, but the Giants managed to turn a 3-6-1 double play to end the game and improve to 98-53, the best record in the Majors.

The Giants overcame an off night from right-hander Kevin Gausman, who surrendered four runs on nine hits over four innings in his shortest start since Aug. 21. Gausman made too many mistakes with his trademark splitter, and the Padres made him pay, banging three solo home runs, two of which came courtesy of Machado, his former Orioles teammate.

Tommy La Stella’s fourth career leadoff home run gave the Giants a quick 1-0 lead against Joe Musgrove, but Machado quickly tied the game in the bottom of the first with a mammoth, 423-foot shot that hit off the third deck of the Western Metal Supply Co. building in left field.

San Diego then surged to a 4-1 lead behind Fernando Tatis Jr.’s two-out RBI single in the second and solo shots from Machado -- a near replica of his first-inning blast -- and Tommy Pham in the third. Gausman entered Tuesday having allowed only two homers on 972 splitters this season, but he gave up three homers on 23 splitters against the Padres.

“I felt really good with it early on,” Gausman said. “I think the one bad split I threw in the first inning was the home run. I really tried to kind of get it out of my head because that’s a big pitch for me. I was just really inconsistent with it tonight.”

Still, the Giants gradually chipped away at the deficit, scoring two runs in the fifth to pull within one before tying the game on back-to-back doubles by Kris Bryant and Crawford in the sixth. Crawford came around to score on Yastrzemski’s sacrifice fly to put the Giants ahead, 5-4, but Austin Nola countered with a game-tying solo shot off Zack Littell in the bottom of the sixth.

It’s been a tale of two halves for Gausman, who logged a 1.73 ERA over his first 18 starts, but has now posted a 5.04 ERA in 13 starts since the All-Star break. Despite the regression, the Giants currently have Gausman lined up to start a potential NL Wild Card Game next month, a show of their confidence in his ability to deliver when it matters most.

“I’m ready for that,” Gausman said. “Obviously, the second half hasn’t gone the way I wanted it to or thought it would. But I’m still very confident in my ability and very confident in my ability in the postseason.”