Eighth seed Martina Hingis trounced Meilen Tu 6-2 6-3 to advance to the third round of the Acura Classic in San Diego.
Hingis was playing her first match since losing to Japan's Ai Sugiyama in the third round at Wimbledon last month.
A two-time champion at this US Open warm-up hard court event, she encountered little trouble disposing of the 91st-ranked American qualifier in 66 minutes.
'Coming off a long lay-off, it's never easy,' Hingis said. 'You feel like you can train forever, but once you play, you feel the rust.
'It's getting to know what to do out there, to construct the points out.
'I didn't play my best tennis, but I know it will come with matches, hopefully. I know I can still get better than what I played today, but it was a solid performance. It was a good win; every one is a good one.'
Hingis became the first player to move into the third round.
She later was joined by second-seeded Maria Sharapova, the former Wimbledon champion who strolled past qualifier and fellow Russian Vasilisa Bardina 6-4 6-1.
Earlier under overcast and muggy conditions, the tournament claimed two more seeds. Russian Elena Vesnina upset 10th seed Anna-Lena Groenefeld of Germany 3-6 6-3 6-3 and 2005 finalist Vera Zvonareva of Russia upended ousted 13th seed Ai Sugiyama of Japan 6-1 7-5.
However, 11th seed Daniela Hantuchova of Slovakia advanced when Kveta Peschke of the Czech Republic retired trailing 6-1 4-0 and 15th seed Katrina Srebotnik of Slovenia beat Marion Bartoli of France 6-3 6-0.
