SAN FRANCISCO -- Mitch Keller received a pitching lesson Tuesday night that he should always remember:

Sometimes it’s best not to throw a strike, especially when it isn’t absolutely necessary.

The Giants taught Keller about the dangers of throwing too many strikes in their 5-4 victory over the Pirates at Oracle Park. The rookie right-hander yielded three consecutive hits on 0-2 pitches, enabling the Giants to score three first-inning runs.

Trailing 5-0, the Pirates nearly rewrote the evening’s script. They amassed four runs in the eighth inning on pinch-hitter Melky Cabrera’s two-run double and Josh Bell’s two-run homer.

Entering Tuesday, the Pirates were tied for the Major League lead with Washington for most runs scored in the ninth inning and later. Each had 94.

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“I like the continued fight, the continued belief that there’s a game to finish and you play until the last out is made,” Pittsburgh manager Clint Hurdle said. However, the Pirates (63-82) clinched their 23rd losing season in the last 27 years, including three of the last four.

Experience will teach Keller, who made his ninth Major League start, that throwing a pitch outside the strike zone often is the best strategy on 0-2 counts. A hitter is unlikely to make solid contact with such a delivery, and even if he takes it, the pitcher’s still ahead on the count. Keller did not stick around to comment afterward.

Stephen Vogt’s two-run single, Kevin Pillar’s single and Brandon Crawford’s run-scoring single were the hits that marred Keller’s evening the most. Vogt completed his four-RBI outburst with a two-run, fifth-inning homer.

Keller, Pittsburgh’s prized pitching prospect, yielded five runs and nine hits in five innings. Reflecting his superior stuff that went to waste, he walked none and struck out seven. His fastball velocity peaked at 98.1 mph, but that didn’t seem to help him when it mattered most.

The Pirates did little offensively against the magical Johnny Cueto, who made his first start of the season following his recovery from Tommy John elbow surgery. The Giants right-hander surrendered just one hit, Kevin Kramer’s third-inning single, while lasting five innings.

Cueto improved to 21-4 with a 2.13 ERA in his career against Pittsburgh, including 9-0, 1.51 in his last 11 regular-season starts.

“It was a good opportunity for some of our guys to learn tonight that it’s not always about velocity,” Hurdle said, referring to Cueto’s dominance. “It’s about reading swings. It’s about locating the ball, finishing pitches and setting hitters up.”