PITTSBURGH -- It was the National League wild-card game 2013. Johnny Cueto, then with Cincinnati, let the Pittsburgh fans get to him with their loud jeers of "Cueeee-toooo" and the Reds lost.

He has not forgotten, even now that he is with San Francisco.

Cueto ran his record against the Pirates to 19-4 and got the win Tuesday as the Giants walloped the Pirates 15-4.

"I wasn't aware of the number," Cueto said through an interpreter of his record against Pittsburgh, "but I know that after I lost the wild-card game against them I told myself I needed to just concentrate and try to win as many games as I can."

In this one, Angel Pagan hit a grand slam and Conor Gillaspie added a two-run homer and finished with four hits and four RBIs for the Giants, who had 22 hits. They have won nine of their past 10 games.

Cueto (11-1) joins Jake Arrieta, Clayton Kershaw and Chris Sale as the only 11-game winners in the big leagues this season. He allowed one run on four hits with six strikeouts and one walk over 6 2/3 innings. He left in the seventh after the Pirates broke up his shutout when Jacob Stallings got his first major-league hit, a double to the left-field wall, and RBI.

On his way from the mound to the dugout, Cueto gave the fans at PNC Park a wave.

"Because they were booing me -- but I like it," he said. "I like that the fans get on me because it inspires me to do better."

Pittsburgh, which has lost six of its past seven games and 11 of its past 13, added two runs in the eighth on David Freese's homer and another in the ninth on Freese's RBI double.

Pittsburgh's Wilfredo Boscan (1-1), making his first major-league start after getting recalled from Triple-A Indianapolis, got rocked for seven runs in the fourth. San Francisco added single runs in the fifth, sixth and seventh and three more in the eighth -- all with two outs.

Pirates left fielder Starling Marte left with two outs in the eighth after he apparently stepped awkwardly while trying to run down a triple hit by Ramiro Pena. The club said he had left foot discomfort.

""I just felt it was best to get him out of the game at that particular time with where we stood," Pittsburgh manager Clint Hurdle said. "There was no need for him to continue trying to play through."

Boscan had made five relief appearances and picked up his first win in earlier call-ups this season.

Through three innings, he breezed along, allowing one hit, striking out two and walking none on 37 pitches.

"The first three innings, he looked really sharp," Hurdle said.

Then it fell apart. Big time.

He failed to get an out in the fourth, and when Boscan was replaced by Arquimedes Caminero, San Francisco had a 7-0 lead.

Joe Panik led off the inning with a single to center. After Brandon Belt doubled and Buster Posey drew the Giants' first walk, Brandon Crawford drew a walk on an 11-pitch at-bat to bring home Panik for a 1-0 lead.

Pagan -- who a night earlier in left field leaped but dropped what proved to be the winning homer -- followed with a first-pitch grand slam, the second of his career, for a 5-0 Giants lead. After Gregor Blanco doubled to center, Gillaspie blasted a homer to right for a 7-0 lead.

"It wasn't going real well in the early going. Their kid was pitching well," Giants manager Bruce Bochy said. "We finally broke through. Crawford's at-bat was the game-changer. Bases loaded, long at-bat, worked him for a walk. I'm pretty sure that took something out of him. Of course, Pagan gets a big hit. It just got contagious after that."

That was the end of Boscan's night. He nearly doubled his pitch count that inning, finishing with 68.

The game was a huge turnaround from Monday night, when the Pirates shut out San Francisco 1-0 in the series opener.

"I'd like to think we're a pretty good hitting team," Bochy said. "We're not getting shut down too often like (Monday) night. We're going to break out of it, and they did it in a big way."

NOTES: San Francisco, as expected, placed 3B Matt Duffy on the 15-day disabled list. Duffy aggravated a left Achilles sprain on Sunday. ... The Giants recalled OF Mac Williamson from Triple-A Sacramento. He is expected to be in the lineup Wednesday. ... CF Denard Span returned to the Giants lineup after sitting out Monday because of a stiff neck. ... San Francisco manager Bruce Bochy is hopeful IF Kelby Tomlinson (sprained thumb) can return before the All-Star break. Tomlinson, who missed his 11th game, had the splint removed Tuesday. ... The Pirates recalled RHP Wilfredo Boscan from Triple-A Indianapolis and gave him his first major-league start Tuesday. He had appeared in relief in earlier recalls. ... Pittsburgh optioned RHP Curtis Partch to Indianapolis. ... Pittsburgh manager Clint Hurdle said RHP Juan Nicasio (restricted list, family matter) could return soon and will go to the bullpen for at least the short term. ... Per Elias Sports, Pirates C Erik Kratz was hitting .045 when he provided the only run in Monday's game with a homer off of Madison Bumgarner, the lowest average of anyone to homer in a 1-0 game (minimum 25 at-bats).