SAN FRANCISCO -- The San Francisco Giants had one hit and trailed the Los Angeles Dodgers by three runs entering the bottom of the seventh inning Wednesday night at AT&T Park.

There was still plenty of time left for Michael Morse to turn back the clock, for rookie Christian Arroyo to announce his official arrival in the major leagues and for Hunter Pence to hit a bases-loaded, walk-off sacrifice fly in the 10th inning in a 10-pitch at-bat for the Giants.

Pence's sacrifice fly off Dodgers right-hander Ross Stripling gave San Francisco a 4-3 victory, but it was Arroyo and Morse who set the stage for his heroics.

Arroyo hit his first major league home run, a two-run shot in the seventh inning off ex-San Francisco reliever Sergio Romo, cutting the Dodgers' lead to 3-2. Arroyo, just 21, played his third big league game since being called up from Triple-A Sacramento.

"It was incredible," Arroyo said. "When I hit it off the bat, I thought it was a double. I was kind of sprinting around the bases. For me, I've never really been a home run guy. As I was sprinting around first base, I kind of looked up and saw the fielders stop and saw the umpire waving. I was like, 'Now you can slow down.' I started rounding second, and I tried to slow down and take it all in."

Morse, who was called up Wednesday from Sacramento, had a pinch-hit solo home run with one out in the eighth inning, tying the game 3-3 in his first at-bat of the season. He fell behind 1-2 in the count then lined Pedro Baez's 97 mph fastball over the left-center-field fence.

Morse said he couldn't help but think back to 2014 when he hit a game-tying, pinch-hit homer in the eighth inning of the Giants' 6-3 victory against St. Louis in Game 5 when they clinched the National League Championship Series.

"That was pretty awesome," said Morse, who returned to the Giants this year after two seasons away. "I think (it was) just what this team needed, a little excitement. The biggest part was the way we came back and won."

Dodgers manager Dave Roberts, gave credit to Morse for a good at-bat against the hard throwing Baez.

"(Baez) was making good pitches and getting the swing and miss with the fastball," Roberts said. "Tried to go to it again and left it just a tick out over. (Morse) got the barrel to it."

Gorkys Hernandez led off the 10th inning with a sharp single to right and stole second base. Conor Gillaspie walked, and the Giants loaded the bases when first baseman Adrian Gonzalez fielded Nick Hundley's bunt and tried to get the force at third but was late with his throw.

Pence fell behind 0-2 to Stripling, swinging at two eye-level fastballs, but worked a full count then kept fouling off more high fastballs. On the 10th pitch of the at-bat, he sent a fly ball to left, driving in Hernandez.

"I was expecting some kind of off-speed," Pence said. "He threw some high fastballs, got ahead of me, and at that point I just had to battle. Just tried to shorten up and fight."

Dodgers left-hander Alex Wood allowed one hit over six shutout innings and opened the game with five straight no-hit frames. He struck out five, walked one and threw 77 pitches in a no-decision.

"He threw a tremendous game," Roberts said. "He was aggressive in the zone. He attacked them and kept the ball down. He was going to throw 75 to 80 pitches tonight. At that point, up 3-0, we've got to close it out. I liked the guys in the spots that they were in for the last nine outs of the game. It just didn't work out."

Corey Seager hit a solo home run in the sixth inning, igniting a three-run rally for the Dodgers.

Giants right-hander Johnny Cueto allowed three runs on seven hits over six innings. He struck out five and walked two.

Derek Law (2-0) pitched a scoreless 10th for the win. Stripling (0-2) took the loss.

Wood didn't allow a hit until Drew Stubbs grounded a sharp single to left leading off the bottom of the sixth inning.

Two innings later, the Giants pulled even on Morse's blast.

"That was quite an energy jolt right there, hitting a huge homer to tie it up and just the emotion and history, the excitement of having him back," Pence said. "And to do that, it's one of those special moments that can change a season."

NOTES: Dodgers LHP Rich Hill (blister) threw 30 pitches to hitters before Wednesday's game without wearing a pad on his injured left middle finger. Hill, who has been on the disabled list since April 17, will throw 30 to 35 pitches on Saturday, either in batting practice or during a minor league rehab assignment. ... Giants CF Denard Span (sprained right shoulder) was placed on the 10-day disabled list. He was injured when crashing into the outfield wall while trying to make a catch on Saturday against Colorado at Coors Field. ... Giants SS Brandon Crawford went on bereavement leave to attend his sister-in-law's funeral. ... San Francisco purchased the contract of 1B/OF Michael Morse from Triple-A Sacramento. ... Giants INF Kelby Tomlinson was recalled from Sacramento, and he lined out as a pinch hitter.