NEW YORK — As if trying to remind himself and everyone else where he’s been and where he’s quite certain he’ll return, Roger Federer thrust his right fist overhead and pointed skyward with his index finger.

The universal gesture for No. 1.

As Federer made that signal, the 1970s song “Still the One” by Orleans rang out through Arthur Ashe Stadium on Sunday, marking the end of the four-time defending champion’s 6-3, 6-3, 6-2 victory over 28th-seeded Radek Stepanek in the U.S. Open’s third round.

Actually, for the first time in a while, Federer is not No. 1 — in the seedings for the hard-court Grand Slam tournament or in the ATP rankings. Those honors belong to Rafael Nadal, who beat Federer in the lopsided French Open and epic Wimbledon finals and last week ended his record 237-week stay at the top.

Federer harbors no doubts that he can re-establish his ranking and his reputation among opponents, both built on the strength of 12 career major singles titles, two shy of Pete Sampras’ record.

“That’s the advantage I have. If I were to win a big tournament again, one of those Slams, whatever, right away I have the invincibility factor again, which is great for me,” he said. “So that’s what I’m working for. I was that close in Wimbledon, so I hope to go a step further and win it this time.”

It’s been a poor-by-his-standards — and, let’s be clear, only by his lofty standards — season for Federer, whose 12 losses already are more than he absorbed in any entire year from 2004-07. His two titles, at minor events, are his fewest entering the U.S. Open since 2002.

“I would love his bad year. … The guy has the best four-year run ever, and we’re all sitting here in shock that it’s not the best five-year run ever. We have to use a little bit of perspective here as far as how good he’s been,” said Andy Roddick, the last man other than Federer to win the U.S. Open, back in 2003, and his potential semifinal opponent this year.

“If you have to hear about anything every day, you start thinking about it a little bit, and maybe that’s where he’s at,” added Roddick, who reached the fourth round by beating No. 31 Andreas Seppi 6-2, 7-5, 7-6 (4).

Roddick will play No. 11 Fernando Gonzalez for a spot in the quarterfinals. Gonzalez, at 28 the oldest man left, beat Jarkko Nieminen 7-5, 6-4, 6-7 (3), 6-1.

Federer’s next opponent is No. 23 Igor Andreev of Russia, who beat No. 13 Fernando Verdasco of Spain in straight sets. In other men’s third-round matches, No. 5 Nikolay Davydenko eliminated No. 26 Dmitry Tursunov, qualifier Gilles Muller fashioned a 6-7 (3), 3-6, 7-6 (5), 7-6 (6), 7-5 upset of No. 18 Nicolas Almagro, and Australian Open runner-up Jo-Wilfried Tsonga lost to No. 15 Tommy Robredo.

Australian Open champion Novak Djokovic needed nearly four hours to get past Marin Cilic 6-7 (7), 7-5, 6-4, 7-6 (0).

The women are a round ahead, and No. 2 Jelena Jankovic reached the quarterfinals by coming back to beat No. 21 Caroline Wozniacki 3-6, 6-2, 6-1. Jankovic is among five women with a shot at reaching No. 1 in the rankings.

Another woman in the chase for No. 1 — and also without a major championship title — is Olympic gold medalist Elena Dementieva, who beat Li Na 6-4, 6-1 and now faces No. 15 Patty Schnyder.

Jankovic will meet No. 29 Sybille Bammer, who got past No. 12 Marion Bartoli 7-6 (3), 0-6, 6-4 in a match that lasted 3 hours, 5 minutes — believed to be the longest women’s match, by time, in U.S. Open history.