Venus Williams gave a signal of intent by thrashing 12th seed Kirsten Flipkens 6-1 6-2 in the first round of the US Open at Flushing Meadows.
The two-time champion went into the clash as an outsider having suffered through two years of illness and injury problems.
The 33-year-old had won just one match since April and had been beaten by Wimbledon semi-finalist Flipkens at the Rogers Cup recently.
But Williams was firmly on top this time against her Belgian opponent as she claimed her first win over a top-20 player since last October.
Elsewhere, Agnieszka Radwanska began her campaign with a straightforward 6-1 6-2 victory over Silvia Soler-Espinosa.
The third-seeded Pole needed just an hour and two minutes to see off her Spanish opponent, whose serve she broke a total of five times.
Soler-Espinosa has never been beyond the third round of a grand slam and proved no match for the former Wimbledon finalist on Arthur Ashe Stadium.
No 15 seed and big home hope Sloane Stephens was given a scare by Luxembourg's Mandy Minella but came through to claim a 4-6 6-3 7-6 (7-5) win.
Fifth seed Li Na enjoyed a much smoother passage into the second round as she recorded a 6-2 6-2 victory over Olga Govortsova.
The Belarusian did not even manage to fashion a single break point against her Chinese opponent, who claimed two service breaks in each set.
Wimbledon finalist Sabine Lisicki also progressed to the next round, the 16th seed seeing off Vera Dushevina 6-3 7-6 (7-3)
But Spain's 18th seed Carla Suarez Navarro had the easiest day of all as she thrashed American teenager Lauren Davis 6-0 6-0 in under an hour.
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