SEATTLE (AP) - Tampa Bay reliever Steve Geltz couldn't prevent the Rays from being swept in Seattle.
Chris Iannetta jumped on a 3-2 pitch from Geltz for a leadoff homer in the bottom of the 11th inning to give the Mariners a 6-5 victory over the Rays on Wednesday and a sweep of the three-game series.
"Bad pitch, bad location," Geltz said.
"Giving up a walk-off homer never feels good. Losing never feels good. It hurts a little bit more, especially when we battle like that and I go in and cost the game. It's tough to pick apart two pitches. He could have just as well swung under it, popped it up or missed it. I just got to execute better."
Iannetta's third homer of the season negated a comeback by the Rays, who overcame an early 4-0 deficit.
"Geltz's M.O. is he's going to throw a lot of fastballs, and if the guy catches up to it, especially those ones at the waist, they can sometimes go a long way," Rays manager Kevin Cash said.
"That's kind of his style of pitching. He's had a lot of success like that. It's just a little inconsistent right now."
It was the second game-deciding home run allowed by Geltz (0-1) in the series, who gave up a three-run homer on his first pitch in the sixth inning of Seattle's 5-2 victory on Monday.
Tampa Bay, which was 2 for 10 with runners in scoring positon Wednesday and 2 for 18 in the series, had the bases loaded with one out in the 10th, but failed to score.
Steven Souza Jr. reached on a one-out walk off Vidal Nuno, advanced on a passed ball and moved to third on Logan Morrison's bloop single to left.
Steve Johnson (1-0) relieved and walked Steve Pearce to load the bases. Kevin Kiermaier fouled out to third and Hank Conger bounced into a force at second.
"I kind of put myself in a tough spot, first time with the bases loaded," said Johnson, who earned his first major league victory since May 29, 2013, when he was with Baltimore.
"I didn't have my best command, but I was able to get a curveball in there for a strike and kind of keep them off balance and make a couple pitches and get out of it."
The Rays tied it 5-5 on Kiermaier's one-out solo homer in the ninth.
With Mariners closer Steve Cishek unavailable after a four-out save Tuesday night, Nick Vincent came on in the ninth to protect a 5-4 lead. After Pearce struck out, Kiermaier lined a 2-0 pitch over the wall in right for his fourth home run.
Nelson Cruz's seventh-inning sacrifice fly snapped a 4-4 tie after the Rays had erased a 4-0 deficit on Corey Dickerson's first career grand slam in the sixth.
Robinson Cano opened the Mariners seventh with a double to right-center and advanced on a wild pitch. Cruz then lofted a fly to left and Cano scored easily ahead of the throw.
Seattle starter Taijuan Walker cruised through five innings, allowing just two hits, before walks set up Dickerson's game-tying slam.
After Brandon Guyer doubled with one out in the sixth, Brad Miller and Evan Longoria drew consecutive walks off Walker, who had walked just three in 32 innings in his first six starts.
Dickerson then lined the first pitch over the center-field wall for his eighth homer.
"He was pitching really good," Dickerson said. "He was working off his fastball, had good off-speed. I had a pretty good swing on a pitch and got us some runs."
The Mariners capitalized on starter Chris Archer's wildness for a three-run first. Norichika Aoki singled and Ketel Marte walked. After Cano struck out, Archer walked Cruz and Kyle Seager to force in a run. Seth Smith then followed with a two-run single up the middle.
Cruz opened the third inning with his sixth homer to make it 4-0.
"We put ourselves in a hole in the first inning," Cash said. "We can't walk guys. This organization is built around pitching. You got to throw strikes and we did not today."
A BIG HIT: Tampa Bay's Brandon Guyer was hit by a pitch in the seventh inning, giving him 11 for the season, tops in the majors and more than 16 teams.
SWEEPSTAKES: The Mariners swept the Rays at home for the first time since Aug. 7-9, 2006.
CANO STAYS HOT: Robinson Cano extended his hitting streak to 11 games with his seventh-inning double. Over that span, he is hitting .449 (22 for 49) with four homers, nine RBIs, four doubles and 10 runs scored.
Rays: 2B Logan Forsythe, who missed Tuesday's game with a bruised left shoulder after being hit by a pitch on Monday, was not in the starting lineup on Wednesday, but was improving. "He's still sore, but actually much better today," manager Kevin Cash said before Wednesday's game. "I'm hopeful for Friday. I'm actually hopeful that it heats up out in the sun and he can be ready late in the ballgame if we need him."
Mariners: Reliever Joaquin Benoit, on the 15-day DL since April 22 with right shoulder inflammation, was scheduled to throw Wednesday, manager Scott Servais said. "Benoit is going to throw a bullpen here today and if that goes OK, we could do a sim (simulated) game this weekend," Servais said. ... Reliever Charlie Furbush, on the DL all season with biceps tendinitis, also had a bullpen workout on Wednesday.
Rays: After a day off, Tampa Bay returns home for a three-game series against Oakland, before heading back out on an eight-game road trip. Right-hander Jake Odorizzi (0-1, 3.10 ERA) starts Friday for the Rays against Rich Hill (4-3, 2.39 ERA). Odorizzi has five straight no-decisions, tying a club record.
Mariners: Right-hander Nathan Karns (3-1, 3.38) starts Friday for Seattle to open a three-game home series against the Angels. Karns has pitched at least six innings in each of his past three starts, allowing four earned runs in 19 1/3 innings with 20 strikeouts.