context: In 2001, the Giants were eliminated from playoff contention on the next-to-last day of the season. Slugging shortstop Rich Aurilia put up stellar numbers (37 HR, 97 RBI, .324 BA) in support of Bonds, who once again gave fans something to cheer about with his single-season record 73 home runs, surpassing Mark McGwires 70 in 1998. The pitching staff was good but not great, with Russ Ortíz (17–9, 3.29) leading a staff that also had Liván Hernández (13–15, 5.24) and Kirk Rueter (14–12, 4.42). Shawn Estes and Mark Gardner had subpar years, but a notable late-season acquisition from the Pirates was superstar starter Jason Schmidt (7–1, 3.39). Robb Nen continued as a dominant closer (45 saves, 3.01 ERA).
question: By how many runs did Bonds improve upon McGwire's record?
answer: 3