The switch-hitting center fielder hit for the cycle in his first four at-bats, sending San Francisco to a 7-3 victory over the Cincinnati Reds on Monday night.
"It hasn't sunk in yet," Winn said.
Winn, who scored twice and finished 4-for-5, led off the first inning against Aaron Harang with a single and the third with his ninth homer this season -- his third in 13 games since being acquired from Seattle on July 30.
"I don't hit a lot of home runs," Winn said. "That's not my game, but I'll take them when they come. My job is to get on base."
The speedy Winn doubled with one out in the fourth and opened the sixth with a triple to right-center, making him the 21st player in Giants history to hit for the cycle and the first since Jeff Kent did so in a 9-8 loss at Pittsburgh on May 3, 1999.
"I knew I needed a triple, but they're so hard to hit that to hit one when you need one for the cycle is almost impossible," Winn said.
It was the first time Winn hit for the cycle in his eight-year major-league career. He is the third player to accomplish the feat this season, joining St. Louis' Mark Grudzielanek on April 27 against Milwaukee, and Washington's Brad Wilkerson on April 6 in Philadelphia.
"I gave him the day off (Sunday) because he'd played every day since we got him," Giants manager Felipe Alou said, adding a smile. "He seems to respond to days off. Maybe I'll give him one tomorrow."
Kevin Correia (2-3) went five innings to beat the Reds for the second time this season. He gave up six hits and four walks with five strikeouts.
The Reds stranded 11 and went 0-for-7 with runners in scoring position.
"We had some chances, and we had some pretty good at-bats, but we had nothing to show for it," interim manager Jerry Narron said. "We just didn't get a big hit when we needed it."
Griffey hit a 1-0 pitch 389 feet to the opposite field in left with two outs in the first inning for his 27th homer. Dunn followed with his 34th, a 429-foot drive halfway up the bleachers in right-center on a 2-2 pitch to give Cincinnati eight sets of back-to-back homers this season.
After Winn's homer in the third, Linden tied the score by leading off the fourth with his third homer on the first pitch.
Kearns hit the first pitch of the fourth inning 418 feet off the facade of the second deck in left to give the Reds a 3-2 lead.
San Francisco took the lead with two unearned runs in the fifth against Harang (8-11). Pedro Feliz reached on rookie third baseman Edwin Encarnacion's throwing error. Feliz moved to second on a groundout and scored the tying run on Linden's single. Mike Matheny gave the Giants a 4-3 lead with an RBI double.
Harang allowed nine hits and four runs in five innings, striking out seven. He knew it was Winn who did him in.
"The second at-bat, on the home run, I was trying to go in, and the ball ran out over the inner half of the plate," Harang said. "That's his power zone. Give him credit. He's fast, and he's out there trying to get on base, but he can hit for power."
- Griffey's homer gave him 1,525 RBI, tying him with Sam Crawford and Jeff Bagwell for 40th on the career list.
- Correia is the 335th pitcher to allow at least one home run to Griffey.
- The Giants activated RHP Armando Benitez from the 15-day disabled list and sent RHP Brian Cooper outright to Triple-A Fresno. Benitez had been on the disabled list with a hamstring injury since April 27.
- Harang is hitless in his last 47 at-bats, tying San Francisco's John Burkett in 1992 for the most consecutive at-bats without a hit since San Diego's Andy Benes was 0-for-50 in 1991.
- Reds 2B Ryan Freel left after six innings with a sore right quadriceps muscle. He was day to day.