San Francisco's Barry Bonds tied Babe Ruth for second place on the all-time home run list with his 714th homer in their 4-2 win at Oakland on Saturday.
Bonds celebrates with his son Nikolai after hitting number 714
The 41-year-old had not hit out of the park in nine games heading into the match but ended his drought with a solo shot into the right-field seats.
Only Hank Aaron, with 755, has now scored more home runs than Bonds.
"It feels great," said a relieved Bonds. "I got a whole lot off my chest. Maybe I'll relax and play better now."
He said he was honoured to be in the same company as the legendary Ruth.
"This is a great accomplishment because of Babe Ruth and what he brought to the game of baseball and his legacy in the game of baseball," Bonds said.
"This and a World Series ring to me would be the ultimate. He changed the game of baseball. It's just great to be in the same class."
Bonds is a seven-time National League Most Valuable Player and also holds the record for the most home runs hit in a season - 73 in 2001.
But despite his record-breaking performances, he remains an unpopular figure with many fans, having been dogged for years by allegations of steroid abuse.
He has gone from denying he used steroids to saying he never knowingly used performance-enhancing drugs.
His personal trainer, Greg Anderson, was one of four men convicted in a steroid distribution ring which rocked the world of athletics and baseball.