Barry Bonds began his chase of Hank Aaron's all-time home run record with his 716th as San Francisco crushed the Florida Marlins 14-2 in California.
Bonds' latest round-tripper was a two-run shot in the fifth inning
The Giants slugger hit his eighth homer of the season and first since passing baseball icon Babe Ruth on 28 May for second place on the all-time list.
Aaron, with a total of 755, is now the only man ahead of him.
But Bonds is unlikely to surpass his mark this season, and the 42-year-old is not certain to play on in 2007.
His achievements have also been overshadowed by allegations of steroid abuse.
Bonds' personal trainer Greg Anderson was jailed for his part in the Balco steroids scandal.
But the left-fielder, whose fitness and productivity have appeared to be on the wane this year, has denied ever knowingly using banned substances.