There was sweet revenge for Serena Williams at the US Open on Saturday as she defeated Russia's Ekaterina Makarova to reach the fourth round at Flushing Meadows.

Makarova had shocked Williams at the Australian Open but, although the first set was tight, the title favourite was never in any trouble before coming through 6-4 6-0.

Williams then revealed she cannot bear to watch matches that she lost, even though they could help her in future encounters.

She said: "I definitely was motivated. Knowing that I lost, it could definitely happen again. I did not want that to happen.

"Whether I learned something (from Australia), I don't know. I really hate watching matches that I lose unless I'm punishing myself. I didn't punish myself."

Williams added: "I used to watch. It was so painful. It was like stabbing myself. I don't like to do that."

The 30-year-old, meanwhile, was so distraught by her first-round loss to Virginie Razzano at the French Open in May that she threw away her dresses.

She added: "I can't even look at pictures. That one is really bad. If I see a picture of the dress, I just don't look at it."

In the next round Williams will play Czech Andrea Hlavackova, who stunned in-form 14th seed Maria Kirilenko 5-7 6-4 6-4 after two hours and 52 minutes in searing heat.

Hlavackova had never played a main-draw match in New York before and, after hitting 45 winners, is

through to the fourth round in singles at a grand slam for the first time.

Second seed Agnieszka Radwanska survived a potentially tricky test against Jelena Jankovic to reach the fourth round.

The Pole has never gone beyond the last 16 at Flushing Meadows and had to come from a set and a break down in her last match against Carla Suarez Navarro, while she is also carrying a right shoulder problem.

But she was the more solid player throughout, moving well and frustrating Jankovic, and coming through impressively to win 6-3 7-5.

Radwanska said: "Today was really, really hot and humid and also windy. It was tough. But I came prepared for that. I was practising here before the match and every day was like that.

"I'm trying to use the ice at the first changeover and trying to stay calm and take the shade as well as much as possible. I was feeling like I was melting there.

"I survived the match. In the second set I was just better for a couple of points."

In the fourth round Radwanska will play in-form Italian Roberta Vinci, the 20th seed, who ousted 13th seed Dominika Cibulkova 6-2 7-5.

Vinci, who won the WTA Tour title in Dallas last weekend, has her work cut out if she is to make the quarter-finals, though, having lost to Radwanska in all their previous four meetings.

Sixth seed Angelique Kerber continued her impressive run through the draw with a 6-1 6-2 victory over Olga Govortsova of Belarus.

German Kerber, whose meteoric rise up the rankings began with a surprise run to the semi-finals here last year, ousted Venus Williams in a tough three-setter on Thursday night but had no such problems this time.

Govortsova had her blood pressure checked at the end of the first set as she struggled with the heat, but was only kept on court for 56 minutes.

Kerber next faces 10th seed and French Open finalist Sara Errani, who was an even easier 6-1 6-1 winner against Russian qualifier Olga Puchkova.

Ana Ivanovic continued her return to form with an impressive three-set win over American rising star Sloane Stephens in the night session on Arthur Ashe Stadium.

It was a repeat of their clash at the same stage last year, which Ivanovic won, but 19-year-old Stephens has improved a lot and took the opening set on a tie-break.

The 12th seed hit back, though, levelling the match and then pulling away in the decider to win 6-7 (4/7) 6-4 6-2.

In the fourth round Ivanovic will play unseeded Bulgarian Tsvetana Pironkova, a former Wimbledon semi-finalist.