Vandeweghe, Bellis ease through in Stanford
Coco Vandeweghe and CiCi Bellis had no trouble as the pair eased through the first round at the Bank of the West Classic.
Vandeweghe, the sixth seed at the WTA Premier event, was on court for just 31 minutes in Stanford on Tuesday.
The American 2012 runner-up and Australian Open semi-finalist took the first set against Ajla Tomljanovic 6-2 before the Croatian retired.
Eighth seed Bellis was also untroubled at the hard-court tournament, easing past Alize Cornet 6-3 6-2.
Qualifiers Veronica Cepede Royg and Caroline Dolehide also progressed.
Cepede Royg battled past Kristie Ahn 2-6 7-5 6-1, while Dolehide, 18, beat fellow teenager Naomi Osaka 6-4 6-2.
Alison Riske claimed a 6-2 6-4 win against Magda Linette and Kateryna Bondarenko was too good for Francesca Schiavone 6-3 6-4.