When Brandon Belt homered in the fifth inning, Tampa Bay starter Chris Archer didn't respond.
Archer, with a serene presence on the mound, retrieved another baseball without much, if any, reaction.
In Belt's next trip up in the seventh, he evoked a much more intense response from Archer. The right-hander, who had only given up one earned run over his four previous starts, tensed up on contact, then hopped with fleeting hope it'd find a glove until ultimately watching Belt's long fly ball hit the base of the center-field fence.
Belt's triple broke a 1-1 tie and paved the way to a three-run rally that lifted the Giants over the Rays, 4-1 in the opener of a three-game series.
Brandon Crawford followed Belt's triple with a two-run home run, his seventh of the season.
Belt finished with three hits, two runs scored and two RBI to lead San Francisco to its third straight win.
"I scooted back (in the batter's box) and it allowed me to relax and see the ball a little bit longer. It helped out today," Belt said.
Madison Bumgarner (11-6) picked up his fourth win in five decisions after he gave up one run on seven hits with 11 strikeouts in seven innings.
"They're pitcher was really good, have to give him a lot of credit," Rays manager Joe Maddon said. "He knows how to elevate, he knows how to get inside on right-handed hitters, his poise was very good."
Archer (6-4) was tagged for four runs on seven hits and three walks in seven innings, while he took the loss for the first time in six decisions.
Jose Lobaton had a double and his first career triple for the Rays, who lost their second straight game.
Tampa Bay jumped ahead in the third inning. Lobaton led off with a double and moved to third on Ryan Roberts' bunt single. Two batters later, Ben Zobrist shot a single to right to give the Rays the lead and snap Bumgarner's scoreless streak at 16 1/3 innings.
Belt evened the score in the fifth, when he hammered a first-pitch changeup deep into the right-field seats.
The Giants put together a two-out rally to take the lead in the seventh. Hunter Pence started it with an infield single and scored on Belt's triple off the center-field fence. Crawford then crushed the following pitch, a fastball, into the right-field seats.
Santiago Casilla tossed a perfect eighth before Javier Lopez and Sergio Romo combined to pitch a scoreless ninth, with Romo picking up his 26th save.
The Giants won three straight games for the first time since July 11-13 against San Diego ... In his last nine starts, Bumgarner has gone at least seven innings and allowed two earned runs or fewer ... Wil Myers went 0-for-3 and saw his 12-game hitting streak come to an end. Rocco Baldelli and Delmon Young share the franchise rookie record with 13 ... Tampa Bay lost for the first time in Archer's last eight starts.