Mark McGwire's assault on the record books began with this grand slam on Opening Day.

McGwire became No. 1 when he hit No. 62 off the Cubs' Steve Trachsel on Sept. 8.

Sosa passed up Big Mac briefly when he hit No. 66 in the 160th game of the season ...

... but Big Mac regained the record with No. 67 the next day.

McGwire's final swing of the season? No. 70, off Carl Pavano of the Expos.

McGwire's X-File.           McGwire's 70 homeruns.