She used to engage in that sort of film work, Williams said, but ‘‘it was so painful; it was like stabbing myself.’’

So even though Williams knew her third-round opponent at the US Open would be the same woman she lost to at the Australian Open, preparing by studying a replay of that January defeat simply was out of the question.

That did not seem to matter at all.

After splitting Saturday’s first eight games against 42d-ranked Ekaterina Makarova, the fourth-seeded Williams got into high gear and breezed to a 6-4, 6-0 victory, reeling off the last eight games.

‘‘Definitely was motivated. Knowing that I lost; could definitely happen again. Did not want that to happen,’’ said Williams, who hit 13 aces to raise her tour-leading total this season to 408.

‘‘I really hate watching matches that I lose, unless I'm punishing myself,’’ added the 14-time Grand Slam champion. ‘‘I didn’t punish myself.’’

She hasn’t been losing much lately.

Since the only first-round Grand Slam exit of her career, against 111th-ranked Virginie Razzano at the French Open May 29, Williams is 22-1 in singles, including the title at Wimbledon and gold medal at the London Olympics.

In New York, Williams has dropped only 12 games entering her fourth-round match against 82d-ranked Andrea Hlavackova, who earned a 5-7, 6-4, 6-4 win over 14th-seeded Maria Kirilenko.

On Saturday, Williams won 32 of 40 points on her serve and never faced a break point.

By the time it was over, she also held a 31-10 edge in winners, moving a step closer to adding a fourth US Open trophy to the ones she won in 1999, 2002, and 2008. The last time Williams played Makarova, the Russian won, 6-2, 6-3, in the fourth round in Melbourne. Williams had seven double faults and 37 total unforced errors that day.

Second-seeded Agnieszka Radwanska handled former world No. 1 Jelena Jankovic, 6-3, 7-5.

Olympic champion Andy Murray, still seeking his first Grand Slam title, eked out a 7-6 (7-5), 7-6 (7-5), 4-6, 7-6 (7-4) victory over No. 30 Feliciano Lopez, who led in each of the three tie-breakers before faltering.

The man Murray beat for the gold at the London Games, Roger Federer, barely looked as if he broke a sweat while dismissing No. 25 Fernando Verdasco, 6-3, 6-4, 6-4.