Serena credits Steffi for mental focus

Williams' quest for calendar year slam begins with easy opening-round win

Defending champion Serena Williams, chasing tennis milestones set by Steffi Graf, credited the retired German star with inspiring her mental discipline on Monday after reaching the second round of the US Open.

World No 1 Williams needed only 30 minutes to advance 6-0, 2-0 over 86th-ranked Vitalia Diatchenko at Arthur Ashe Stadium, taking her 22nd consecutive US Open triumph since losing the 2011 final to Australian Samantha Stosur when the Russian retired with a left foot injury.