Gonzalez sent the first pitch from Cubs left-handed reliever Sean Marshall an estimated 462 feet for the 29th third-deck homer in the history of Coors Field, where a sellout crowd of 48,065 witnessed a full game of eye-popping feats.
The homer was Gonzalez's fourth in as many games, and his team-leading 21st of the season. It was also his eighth off a left-handed pitcher. For good measure, Gonzalez also had a key sacrifice fly in the seventh inning.
The last Major Leaguer to clinch a cycle with a game-winning homer was the Red Sox's Dwight Evans against the Mariners on June 28, 1984.
"You can't do baseball much better than that," Rockies manager Jim Tracy said.
Even without the finish, Gonzalez had a tremendous night. He singled in the first inning, tripled in the third and doubled in the fifth -- all off Cubs starting pitcher Tom Gorzelanny. The sac fly was against Gorzelanny as well.
Incidentally, Gorzelanny started for the Cubs the last time a Rockies player hit for a cycle. Troy Tulowitzki accomplished the feat on Aug. 10, 2009, in an 11-5 Rockies romp. In this one, the Rockies needed every one of Gonzalez's successful swings.
It didn't matter who Gonzalez faced or where the pitchers threw the ball, Gonzalez swatted it.
"I tried a few different locations and instead of being able to do what I was supposed to do, he hit them," Gorzelanny said. "I think the last hit he got I think he was in the other batter's box."
Marshall admitted playing with fire.
"He's the guy in the lineup that we didn't want to beat us," Marshall said. "I went in and challenged him, and he beat us."
Gonzalez readily admitted he watched every inch the ball traveled, partly out of shock.
"I didn't even think I hit it that hard," Gonzalez said. "I think the pitch helped me, too. It was 90-something, inside, and hit right on the barrel. It was unbelievable. I didn't even know that ball was going to end up in the third deck."
All six Rockies cycles, and all three by opponents, occurred at Coors Field.
In addition to those by Gonzalez and Tulowitzki, the other Rockies cycles were by Dante Bichette on June 10, 1998; Neifi Perez on July 25, 1998; Todd Helton on June 19, 1999; and Mike Lansing on June 18, 2000.
Opposing teams' cycles were accomplished by the Cardinals' John Mabry on May 18, 1996; the Astros' Craig Biggio on April 8, 2000; and the Giants' Fred Lewis on May 13, 2007.
Gonzalez, 24 and looking like one of baseball's next-generation stars, has hit safely in five of the past six games to lift his batting average to .321, second in the National League behind the Reds' Joey Votto. And Saturday was only the beginning of him turning the corner after being so sick Friday that he didn't eat before going 4-for-6 with a double and a homer.
Each big night is an opportunity to remember what many fans of the Rockies and Gonzalez call one of the biggest oversights of this season.
"Tonight just reinforces how special a player that he is -- how unfortunate it is that he didn't make the All-Star team," said Rockies closer Huston Street, who joined the team with Gonzalez in the winter 2008 trade that sent Matt Holliday, who wore the same No. 5 Gonzalez wears, to the Athletics.
"Most of the time when he goes to the plate, we're expecting something good is going to happen," said catcher Miguel Olivo, who hit a three-run homer off Gorzelanny in the second inning.
Gonzalez's homer was the sixth game-ending long ball for the Rockies this season. Chris Iannetta has had two, and Olivo, Jason Giambi and Seth Smith have knocked one apiece.
Several of those were seen as season-changing plays. But fact is the Rockies are eight games behind the NL West-leading Padres and 5 1/2 behind the division-rival Giants in the Wild Card race. As rousing as Saturday's victory was, it can't be the last such celebration.
"Whenever we start playing really well, something magical happens," Gonzalez said. "I hope I'm not going to be the last one."