Serena Williams

NEW YORK — Remember when Serena Williams was chastised for not taking tennis seriously enough?

For picking and choosing where to play and when to expend full effort? For not devoting herself fully to the sport and instead taking time to dabble in acting, fashion design or other interests?

Well, maybe she knew exactly what she was doing all along, because it certainly appears as though it’s all worked out pretty well on the court. After nearly a full year off thanks to a series of health scares, Williams is right back at the top of her game — and at the top of the sport — and she can prove that at the U.S. Open.

The season’s last Grand Slam tournament is scheduled to start Monday, so long as Hurricane Irene doesn’t get in the way.

“I’m just here to play one match, and the next match, and hopefully I can get to seven wins,” Williams said, referring to the number of victories required to win a Grand Slam title. “That’s what I’m here for.”

She leads all active women with 13 major singles titles, the sixth-highest total in history, and won the U.S. Open in 1999, 2002 and 2008.

But the 29-year-old American missed last year’s tournament at Flushing Meadows, part of a lengthy absence from the tour after two foot operations from getting cut by glass at a restaurant in July 2010, then clots in her lungs, and then a gathering of blood under the skin of her stomach.

Since returning to action in June at a grass-court tuneup for Wimbledon, she has gone 16-2, making her the woman to watch in New York, along with Maria Sharapova (whose three major titles include the 2006 U.S. Open). Most of the attention in the men’s field is, as usual, on the top trio of Novak Djokovic, Rafael Nadal and Roger Federer, who have combined to win 25 of the past 26 Grand Slam championships.

New No. 1 Djokovic is having one of the greatest tennis seasons in history: 57-2 with nine titles, including at Wimbledon and the Australian Open.

Showing off a renewed dedication to fitness and those same old stinging serves — the most dangerous in women’s tennis — and powerful groundstrokes, Williams won tournaments at Stanford and Toronto this month on hard courts.