The 2006 tennis season has begun, not surprisingly, with another title for Roger Federer. The 24-year-old Swiss no. 1 triumphed in his first tournament of the season for the third straight year, defeating 19-year-old Gael Monfils on Saturday in the Qatar Open,6-3,7-6 (5). It was his second straight title in Doha, both without dropping a single set.

We last saw Federer in November, when he lost a shocker to David Nalbandian at the Tennis Masters Cup in Shanghai after relinquishing a two-sets-to-none lead. At the time, he was coming off an ankle injury that forced him to use crutches. He wore a brace in Doha last week, but pronounced himself fit after defeating the talented but inconsistent Monfils.

Federer was remarkable in 2005: 11 titles (including two Grand Slams) and an overall record of 81-4. Can we expect as much, or even more, in 2006? Here’s glance at what the new year should bring to the world of tennis.

MEN

ROGER FEDERER Federer can make 2006 more memorable than 2005 if he does one thing: Win the French Open. It’s foolish to bet against him at the other majors, but we’ll be conservative and pick him to win Wimbledon and one other (not the Australian Open, which begins a week from today). Federer says he plans to volley more this year – yes, even he wants to improve. We’ll let you know if it actually happens.

RAFAEL NADAL Nadal will likely skip Australia, owing to a lingering left foot injury. The world no. 2 has been recovering slowly, and may not be in top form until the clay court season arrives in April. After a phenomenal 2005, Nadal has some important adjustments to make this season: fewer tournaments, a better serve, and more depth on his shots. Time will tell if he can sustain his high-energy play over a long career, an achievement not common among clay courters.

ANDY RODDICK As well as the American played last season (five titles and runner-up at Wimbledon), the year will be remembered for several disappointing losses, first in Australia (Lleyton Hewitt), then in Paris (lost a two-sets none lead in the second round) and worst of all, at the U.S. Open (first round defeat at the hands of no. 69 Gilles Muller). Roddick says he will play more aggressively in 2006, a welcome change considering how lethargic he was at times in 2005, especially on his service return games. With Nadal, Marat Safin, and Andre Agassi out of Australia, Roddick should settle for nothing less than the final. We’ll pick him to win in an upset.

ANDRE AGASSI Soon to be 36, Agassi will not begin his season until next month in Delray Beach, Fla., owing to an ankle sprain he sustained during a friendly game of racquetball. Expect to hear lots of talk about Agassi’s retirement, but don’t expect him to go anywhere. He is open to playing through 2007, though his health – mostly a testy sciatic nerve in his back – could dictate otherwise. Here’s hoping he will skip the French Open, too, as he has no chance to compete there and perhaps a better chance of injuring himself. A visit to Wimbledon would be welcome, and the U.S. Open, where he put Federer to the test in last year’s final, must be at the top of his list.

Agassi’s ranking may suffer this year for lack of appearances, but his play, if all goes well, will not. He is currently tied with Jimmy Connors for most top 10 finishes with 16.

WOMEN

THE WILLIAMS SISTERS Early indications are not good for anyone hoping that the most famous sisters in tennis, Serena and Venus Williams, will improve upon their average performances in 2005. Playing at an exhibition in Hong Kong last week, Serena lost her first match of the year in straight sets to Elena Dementieva. She then withdrew from the event with inflammation in her left knee. Serena, the defending champion in Australia, has not won a match since the third round of last year’s U.S. Open. Her hopes for a repeat down under, as well as a Grand Slam title later in the year, 944 2174 1052 2185look grim unless she decides to train.

As for Venus, she lost to Lindsay Davenport in Hong Kong on Friday and complained of a hip ailment that she says has defied diagnosis. Venus surprised everyone last year with her victory at Wimbledon. We would be doubly surprised if she did it again.

KIM CLIJSTERS Finally a Grand Slam champion, Clijsters is primed for a stellar 2006.The no. 1 ranking should be hers by next month, and she has a real chance of winning three Grand Slam titles this year. Clijsters plans to retire at the end of 2007, so she had better get her winning done now.

MARTINA HINGIS Yes, the former world no. 1 has returned at the ripe old age of 25. Her feet, the source of her retirement, are better, and her serve is a bit stronger. Of course, her competition is much improved, too. Last week, Hingis swept aside three average players in her first tournament in three years, eventually losing to Italy’s Flavia Pannetta. She will play Justine Henin-Hardenne this week in what might be a better measure of her prospects, though Henin-Hardenne is returning from injuries and often struggles to beat lesser players early in tournaments. Hingis probably has what it takes to return to the top 25, even the top 15, but it’s hard to see her as a major threat.

MARIA SHARAPOVA She is troubled by a shoulder injury and says some of the blame goes to the type of balls used on the tour (Australia will use Wilson, seen as a lighter brand, so Sharapova should be happy there). If she does not win a Grand Slam title this year, expect the voices of doubters to grow quite loud.

LINDSAY DAVENPORT The American promises to play fewer tournaments this year. After a number of near misses in the last two seasons, including a championship point at Wimbledon, she should win her last Grand Slam title in 2006.

ON THE MOVE

For the men, Monfils shows early indications of moving up the ladder, perhaps inside the top 15. For the women, keep an eye on 16-year-old Nicole Vaidisova and don’t be surprising if she finishes the year ranked higher than either of the Williams sisters.

OTHER NEWS

The testing of instant replay has begun, and it should appear in at least one major tournament by this summer and then the U.S. Open. The plan is to give players a number of challenges, as in the NFL. One can only hope that officials – and players – will quickly conclude that it makes perfect sense to forget challenges and use the instantaneous images to review any shot worth a second look.

tperrotta@nysun.com