The St Louis Cardinals' first baseman hit a pair for the second consecutive night during a 14-4 rout of the Florida Marlins in Miami. The barrage kept "Big Mac" on course to beat the record of 61 set by Maris of the 1961 New York Yankees, who outslugged his team-mate Mickey Mantle when both chased Babe Ruth's mark of 60 set in 1927.
"It will probably sink in on the flight home," McGwire said. "I was more surprised when the first one went out. It was three feet off the ground and that is why I put my fist in the air - I was amazed that I golfed it."
McGwire's two blasts came after Sammy Sosa, the Chicago Cubs outfielder, hit his 56th homer of the season in a 4-2 win against Cincinnati Reds.
Homer No 58 for McGwire came on a 2-1 pitch from the Florida reliever, Brian Edmondson. The ball flew 497ft into the left-field upper deck of the Joe Robbie Stadium - the third-longest hit in the ballpark's six-year history. In the eighth, he made it 59 when he clubbed the first pitch from Rob Stanifer 458ft to left-centre.
The previous day, McGwire hit two homers against Florida to break the National League record of 56 set in 1930 by Hack Wilson, of the Chicago Cubs.
The Cardinals have 23 games remaining in the regular season and McGwire is on pace to hit a record-breaking 68 homers.Reuse content