Gyorko led off the eighth inning with a go-ahead homer, then helped trick a base runner into a game-ending double play to help the Padres to a 2-1 win over the Colorado Rockies.
The rookie's home run off Matt Belisle (5-6) came right after the Rockies tied the game at 1 in the eighth inning on a San Diego error.
Gyorko's 17th homer just barely cleared the right field wall as it hit the top padding and avoided the leaping attempt of right fielder Michael Cuddyer.
"I faced him a number of at-bats against him throughout the year," Gyorko said. "He's got good command. I know he likes to try get ahead with his fastball away and I just sat on it and put a good swing on it. I wasn't sure if it was going to get out or not. It was just enough to sneak over."
Gyorko had been hitless in five at-bats against Belisle this season with two strikeouts.
Arenado lifted a fly ball to center field. But rather than retreating to first, Cuddyer slid as Gyorko deked him into thinking there was a play at second base.
When Cuddyer realized Arenado hit a fly ball, he ran back to first. But Alexi Amarista made the catch and easily doubled Cuddyer off first to end the game.
"A great play," San Diego right fielder Will Venable said.
"Middle infielders try to do that all the time, sometimes it works better than others. Fortunately, for us, it worked out great."
Gyorko leads all major league rookies in homers and extra-base hits (41) and is third in RBIs with 44.
Luke Gregerson (6-7) got the win and Street picked up his 28th save by getting the final three outs.
The Rockies spoiled a strong outing by Padres starter Tyson Ross, who allowed just three hits in seven innings.
"I think there have been times, where I thought he had maybe thrown better," Padres manager Bud Black said. "It's a great sign to do what he did (Saturday) when on given nights I thought he throw the ball overall better."
Hundley applied the tag in time, but Culberson's slide ripped the glove off Hundley and the ball came out.
Amarista drove in San Diego's first run with a bases-loaded, infield single in the first inning.
The Rockies had just two base runners reach second base against Ross. The closest Colorado came to scoring on Ross came after Helton doubled to lead off the seventh.
With one out, Yorvit Torrealba hit a low line drive to right field that Venable went for and caught. Venable then doubled Helton off second.
"(Ross) has gotten better," Colorado's Troy Tulowitzki said. "He kept us off balance. He did a good job and as the game went on, he gained some confidence because he was having success."
Colorado's Tyler Chatwood allowed one run and five hits in his six innings.
Denorfia and Gyorko had consecutive one-out singles in the San Diego first.
After Jesus Guzman drew a walk with two outs, Amarista drove in a run when his ground ball deflected off the Chatwood's glove for an infield single.
Chatwood was making his second start since coming off the DL last Sunday. In his first start back, the right-hander lasted just two innings against Cincinnati when he took a line drive off his right thumb and had to leave the game.
Rockies CF Dexter Fowler was held out of the starting lineup after he aggravated a right knee sprain that recently caused him to miss six games. ... The Eastlake Little League team from Chula Vista that won the U.S. championship two weeks ago was honored in a pregame ceremony. ... Colorado RHP Chad Bettis (0-3, 5.45 ERA) faces San Diego RHP Ian Kennedy (6-9. 4.96) in the season finale between the clubs.