NEW YORK — So, Victoria Azarenka, what went through your mind as your high-tension, high-quality US Open quarterfinal victory over defending champion Sam Stosur stretched into a third-set tiebreaker?

‘‘You don’t want to know what I kept telling myself,’’ Azarenka deadpanned Tuesday. ‘‘I would have to beep that, I think.’’

She went on to offer a cleaned-up version of what her thoughts had been — ‘‘Don’t be a chicken’’ — while cobbling together a 6-1, 4-6, 7-6 (7-5) rain-interrupted win that eliminated Stosur, put the top-seeded Azarenka in her first semifinal at Flushing Meadows, and assured her of retaining the No. 1 ranking no matter what happens the rest of this week.

‘‘Definitely I don’t want to stop. I really want it bad,’’ Azarenka said about the prospect of adding a second Grand Slam trophy to the one she earned in January at the Australian Open. ‘‘I'm going to do absolutely everything I have, you know, to give it all here.’’

Thanks to off-and-on showers, she was the only player who got to enjoy a women’s singles victory at the US Open Tuesday. The other women’s quarterfinal on the schedule was suspended because of rain, and four-time major champion Maria Sharapova will be trailing 2007 Wimbledon runner-up Marion Bartoli, 4-0, when they resume Wednesday.

They were allowed to head to their hotels before 6 p.m., because the tournament wanted to free up Arthur Ashe Stadium for the night session and what was supposed to be the main event: 2003 US Open champion Andy Roddick’s bid to postpone retirement yet again by beating 2009 champ Juan Martin del Potro in the fourth round.

That match was also suspended because of rain, with the American leading, 1-0, in a first-set tiebreaker.

Roddick surprisingly announced last week, on his 30th birthday, that this tournament would be the last of his career. Since then, he picked up two victories over players ranked 43d and 59th, but the No. 7-seeded del Potro figures to provide more of a challenge.

Fourth-seeded David Ferrer advanced to the quarterfinals, coming back from an hour-long rain delay to close out a 7-5, 7-6 (7-2), 6-4 victory over No. 13 Richard Gasquet.

As accomplished as Stosur is, she never had taken so much as a set off Azarenka in six previous tour meetings, including one match in qualifying.

That changed in Tuesday’s second set, although forcing a third might not have given Stosur all that much self-belief. And in the end, Azarenka improved to 11-0 in three-setters this season, while Stosur fell to 9-7.

Serving at 5-all in the third, Azarenka faced a break point and responded the best way possible, delivering a 92 m.p.h. ace, her only one of the match.

Her serve is not exactly her strongest stroke, and Azarenka double-faulted five times, including while ahead, 5-3, in the tiebreaker.

Azarenka used a swear word at her news conference to describe the second fault there, which landed several feet long. That was part of a topsy-turvy tiebreaker, in which Azarenka went ahead, 4-0, and Stosur took five of the next six points to make it 5-5.

But that was when Azarenka buckled down.

‘‘For sure, she really pushed me to dig deep,’’ Azarenka said.

On the next point, a Stosur groundstroke clipped the net and went over, and Azarenka had the presence of mind to respond with a drop-shot winner. That set up match point, which fittingly was a hard, 10-stroke exchange.

Eventually, Stosur sailed a backhand long as she dropped to a knee at the baseline.