NEW YORK (AP) Jeremy Affeldt watched San Francisco manager Bruce Bochy walk from the dugout to the mound, over and over again.

''He got his cardio in. He did a lot of trips,'' the reliever said.

With All-Star closer Brian Wilson out for the season following elbow surgery, Bochy used six relievers in a 10-inning thriller Friday night. Clay Hensley came in and escaped a two-on, none-out jam in the 10th to preserve a 4-3 victory over the New York Mets.

Hector Sanchez tagged out Kirk Nieuwenhuis to prevent the Mets from winning in the ninth, then singled home the go-ahead run off Frank Francisco (0-1) in the 10th.

''This is going to be a gut-check for us,'' said Giants starter Barry Zito, who got out of his own bases-loaded trouble in the fifth. ''We've got studs down there in the 'pen, and they're ready for the challenge.''

Bochy used 20 of 24 available players and made three double-switches - two in the ninth and one in the 10th.

''That would have been a tough one to lose,'' he said.

San Francisco took a 3-0 lead in the third when Angel Pagan homered in his return to New York, Buster Posey hit an RBI double and Jonathon Niese threw a run-scoring wild pitch.

New York's first two hits off Zito were both home runs, by Jason Bay in the fourth and Nieuwenhuis in the fifth, which made the rookie the first Mets left-handed hitter to clear the left-field wall at Citi Field. It took 250 games and 4,155 at-bats, according to STATS LLC. And it took reconfigured dimensions, too.

Guillermo Mota and Affeldt followed Zito and retired nine straight batters. But Bay reached on an infield hit to deep shortstop off Santiago Casilla leading off the ninth. Javier Lopez came in and got pinch-hitter Lucas Duda to fly to right, then Lopez threw a wild pitch, Nieuwenhuis walked and Josh Thole singled to right to drive in the tying run.

Sergio Romo (1-0) relieved with runners at the corners and, with the infield in, pinch-hitter Mike Baxter hit a grounder to first baseman Brandon Belt, who threw home in time for Sanchez to tag Nieuwenhuis. Romo then struck out Ruben Tejada.

''We had the opportunity to win several times,'' Mets manager Terry Collins said.

Then in the 10th, Francisco walked Melky Cabrera on four pitches leading off, and with one out Cabrera stole second on a pitchout. After Gregor Blanco flied out, Nate Schierholtz was intentionally walked and Sanchez singled to shallow center. It was a rare key hit for the Giants, who went 1 for 11 with runners in scoring position through nine innings and 2 for 14 overall, leaving them with a .195 RISP average for the season (26 for 133).

Bochy had left Sanchez in the game in the ninth when he could have moved Posey from first to behind the plate. But he liked the way Sanchez was catching.

''He trusts me,'' Sanchez said. ''This is great for me.''

But the Giants didn't make it easy on themselves.

Daniel Murphy and David Wright singled to start the 10th, Hensley relieved in the final double switch and Ike Davis advanced the runners with a groundout.

With the infield in, Hensley struck out Bay.

''I really didn't want to give him anything to hit, because the base was open, but at the same time, they did have a lefty coming up,'' Hensley said.

Duda fouled off four straight pitches, took two, then flied out as Hensley got his first save since Oct. 3, 2010, for Florida.

''I was pretty fired up,'' said Hensley, a 32-year-old right-hander. ''Those are things I think I've learned in the past, that you've got to breathe and just kind of let your stuff work for itself and try to let the situation kind of take hold of you.''

NOTES: Posey singled and hit an RBI double in his first two plate appearances for San Francisco, giving him nine hits in a span of 14 at-bats. Posey was retired in his next two at-bats. ... Zito allowed two runs and four hits in five innings, leaving him with a 1.71 ERA. He retired Davis on a popup to end the fifth. ... San Francisco won its third straight and sent the Mets to their third consecutive loss. ... Wilson had elbow ligament replacement surgery Thursday. Dr. James Andrews operated on Wilson, as he did when the right-hander was at LSU in 2003. ''It went great,'' Bochy said. ''He's starting his rehab, which is a long road he'll go down, but he's been down it before and he knows what's ahead of him.'' ... INF Ryan Theriot missed the team flight Thursday because he was sick. Bochy expects him to arrive in New York on Saturday. ... 2B Freddy Sanchez (right shoulder) worked out in Arizona but wasn't ready to start a rehab assignment. ... Pedro Sandoval extended his hitting streak at the start of the season to 13 games.