PITTSBURGH -- Jack Suwinski hit his third homer of the game in the ninth inning, giving the Pittsburgh Pirates a 4-3, walk-off victory over the San Francisco Giants on Sunday to avoid a three-game sweep.

The rookie drove a slider from sidearming Tyler Rogers (0-3) to right for his second game-ending home run of the season after connecting for one June 4 against the Arizona Diamondbacks.

Suwinski became the first rookie in major league history to have a three-homer game that included a walk-off home run, according to the Elias Sports Bureau. He also became the first Pirates player with multiple walk-off home runs in a single month since Wally Westlake in September of 1947, according to ESPN Stats & Information research.

"I was just like, 'No way, man. No way that's going,'" Suwinski said. "That guy is hard to hit off of. Coming from that low under there, it's not an easy at-bat."

Pirates manager Derek Shelton spoke with Suwinski in the bottom of the eighth, asking if he was ready to go deep a third time. Shelton said he was told, "No."

"I was not trying to think about that," Suwinski said. "You start trying to do too much and then you just blow it or whatever. I was just trying to not think about that and just focus on what the pitcher had."

The Pirates will be adding another potentially impactful rookie on Monday when they recall shortstop Oneil Cruz, the organization's top prospect, from Triple-A Indianapolis. Shelton confirmed after the game that Cruz and outfielder Bligh Madris will be brought up to the major league club. Cruz, who appeared in two games for the Pirates last season and hit a home run, is hitting .233 with nine home runs, 35 RBIs and a .761 OPS for Indianapolis this season.

Suwinski is the second Pirates rookie to hit three homers in a game, joining Andrew McCutchen (Aug. 1, 2009). Josh Bell was the last player to hit three in a game for Pittsburgh on July 1, 2019.

The 23-year-old Suwinski took a sinker from starter Alex Cobb deep for a solo shot in the fourth before doing the same to Sam Long for a 3-2 lead in the sixth. He has 11 home runs in 47 games this season, tied with Bryan Reynolds for the team lead.

Thairo Estrada homered off Pittsburgh closer David Bednar leading off the top of the ninth, tying the game at 3. Bednar (3-1) was working his second inning of relief and struck out two of the final three batters to end the ninth.

Mitch Keller gave up two runs (one earned) on three hits with four strikeouts in six innings for the Pirates, extending his streak of starts with fewer than three runs allowed to four. He has surrendered eight earned runs in 28 1/3 innings (2.54 ERA) in his last six games (four starts).

"It's definitely nice, but tomorrow you have to flush it like nothing happened," Keller said. "You have to keep going. That's my mentality. ... Just keep a good routine and keep going."

Cobb allowed two runs on four hits in four innings during his return from the 15-day injured list with a neck strain.

"I think he was solid after a long layoff," Giants manager Gabe Kapler said. "First and foremost, he came out healthy. I know he's not going to be happy not coming out of the game with a lead, but got through exactly what our pitch count was for him."

After an error and two walks loaded the bases for San Francisco with no outs in the first, Joc Pederson dribbled a two-run single past Hoy Park at second base.

Park went yard on a sinker from Cobb to right-center field in the third, cutting it to 2-1 with his first home run of the season before Suwinski's first homer an inning later.

"Sometimes you just have to tip your cap," Cobb said. "It was a bad pitch (to Suwinski). But it's his day. Sometimes the story is about one guy. It was an impressive game by him."

The Associated Press contributed to this report.