The Braves were within one out of taking control of the NL division series, but a 30-year-old journeyman infielder who wouldn't have been playing if not for season-ending injuries to Chipper Jones and Martin Prado simply couldn't catch the ball.
Buster Posey's grounder went right under Conrad's glove, his worst miscue yet in a performance that might speed up the retirement of Braves manager Bobby Cox.
Freddy Sanchez raced around with the go-ahead run, and Brian Wilson shut down the Braves in the ninth to give the Giants a 2-1 lead in the best-of-five series.
San Francisco can close it out Monday night. For Conrad, the memories of this game will linger for a lifetime.
Atlanta did nothing against Jonathan Sanchez, managing only two hits in 7 1-3 innings, and the Giants led 1-0 on an unearned run provided by Conrad's second error, that dropped popup in short right field in the second.
But when pinch-hitter Eric Hinske lined a two-run homer off Sergio Romo in the eighth, the Braves took a 2-1 lead.
Unfortunately for Atlanta, there was no Billy Wagner to close it out. He was removed from the roster before the game with a pulled muscle on his left side.
Rookie reliever Craig Kimbrel was within one out of a save before the Giants rallied. Aubrey Huff tied it with a run-scoring single off Mike Dunn. Then, Posey hit a grounder to just the right man.
It skidded right through Conrad and into center field.
The wild finish overshadowed Jonathan Sanchez's brilliant performance - he didn't allow a hit until the sixth - and Hinske's dramatic homer, which carried the Braves to within one strike of having a chance to close out the series at Turner Field.
Conrad's blunders cost them.
He was one of the last guys to make the Braves roster out of spring training and spent his first full year in the big leagues. Conrad was primarily a backup, though he did provide one of the season's most dramatic moments with a pinch-hit grand slam that capped a seven-run ninth inning and a 10-9 victory over Cincinnati in May.
Then Jones hurt his knee, and an injury finished off Prado for the season, too. Down the stretch, the Braves were forced to go with Conrad at third base.
His defense was so shaky that Cox swapped him with Omar Infante before the crucial last game of the regular season with the Braves trying to wrap up the wild card, moving Conrad to second because he was having trouble making accurate throws from third.
His arm wasn't the problem in Game 3.
Now, the Braves will need to win the final two games to extend Cox's career to at least the NL championship series. One of baseball's winningest managers is retiring at the end of a season that is one loss from being over.