SAN FRANCISCO -- Conor Gillaspie hit his first Major League home run in the Giants' 7-0 victory Tuesday night over the Colorado Rockies, but the rookie didn't round the bases in ordinary fashion. You might say he had a strange trip, literally and figuratively.

With two outs in the seventh inning and Brett Pill on first base, Gillaspie recorded the fourth inside-the-park homer by a Giants player in AT&T Park history. The left-handed batter connected with the first pitch he saw from Colorado Rockies right-hander Esmil Rogers and drove it to right-center field. As Rockies right fielder Ty Wigginton's throw eluded second baseman Mark Ellis, the cutoff man, Gillaspie received third-base coach Tim Flannery's signal to head for home. But Gillaspie stumbled and fell as he rounded the bag. Realizing that the Rockies were slow to relay the ball home, Gillaspie regained his footing and slid home headfirst as catcher Wilin Rosario couldn't hang onto the throw.

Gillaspie remained sprawled for an extra second or two, almost burying his head in the dirt, before rising and picking up his bat.

"Honestly, I was pretty embarrassed," Gillaspie said. "I didn't want to get up."

Gillaspie had accumulated only 14 at-bats before Tuesday, mostly as a pinch-hitter. But manager Bruce Bochy liked the quality of the 24-year-old's opportunities. "Disciplined" was how Bochy described Gillaspie's plate approach.

"He's one of the most improved players I've seen in this system," Bochy said of Gillaspie, who hit .297 with 11 homers and 61 RBIs in 124 games this year with Triple-A Fresno.

But Gillaspie confessed to feeling slightly rusty at the plate, though he also hit a fourth-inning single.

"Honestly, I don't know how it happened," Gillaspie said of his line drive that short-hopped the wall near the 421-foot marker. "He threw a fastball and I was ready to hit it. I just tried to put a good swing on it."

Gillaspie said that after he fell, "I thought for sure I was going to get thrown out. If I wouldn't have fallen I think I would have had it easy. But it worked out and it's pretty exciting."

Television replays indicated that Gillaspie might have missed third base. "Oh, I hit third base," he said. "I just hit myself coming around third base."

Nevertheless, Gillaspie decided to try for home.

"At that point, I looked over and I saw the guy didn't have the ball. He was still trying to get it," Gillaspie said. "I figured I'd just go for it. I was happy just to hit the ball."

Gillaspie, who played briefly with the Giants in 2008, is the first Giants player to hit an inside-the-park homer for his first big league home run since Dax Jones did so on Aug. 18, 1996, in Philadelphia.