Keys leads American charge
It was generally a good day for the hosts as the BNP Paribas Open began at Indian Wells.
Of the seven American players in action in the first round of the women's singles, four emerged victorious.
Madison Keys is a teenager of whom much is expected and a thumping 6-2 6-1 victory over Tsvetana Pironkova was just what she needed after an up and down start to the year.
Wild card Shelby Rogers made the best start of anyone in beating in-form Petra Cetkovska 6-0 6-4 while Lauren Davis defeated Chan Yung-jan 6-4 6-3 and Varvara Lepchenko was a 6-2 6-2 winner over Alison van Uytvanck.
There was disappointment, though, for Alison Riske, Christina McHale and Allie Kiick.
McHale reached the final in Acapulco last week but lost 7-6 (7/4) 6-4 to Australian Open quarter-finalist Casey Dellacqua.
Riske won the first set against Bojana Jovanovski before going down 3-6 6-3 6-3 and qualifier Kiick fell 6-4 6-0 to Japan's Kurumi Nara.
Two-time grand slam semi-finalist Vera Zvonareva, who won the Indian Wells title in 2009, is working her way back after a long lay-off with injury and illness but could not turn a good start into victory over Shuai Peng.
Russian Zvonareva has won just one match since returning to the tour at the start of the season and lost out 4-6 6-0 7-5 to China's Peng.
The second half of the women's first round will be played on Thursday while the men's main draw also begins.
The stand-out match sees Lleyton Hewitt face fellow Australian Matt Ebden while home hopes Sam Querrey and Jack Sock are in action.
In the fourth match on Court 2, Martina Hingis plays her first match of the year in doubles alongside Sabine Lisicki against Australian pair Dellacqua and Ashleigh Barty.
Hingis returned to the main tour last year after a break of six years but won only three matches in five tournaments and has been coaching German Lisicki this season.
The draw for the men's doubles threw up some eye-catching partnerships, not least the all-Swiss pairing of Australian Open champion Stanislas Wawrinka and Roger Federer, who won an Olympic gold medal together in 2008.
Andy Murray pairs up with former Wimbledon doubles champion Jonny Marray and they will take on France's Gael Monfils and Argentinian Juan Monaco in the first round.