Roger Federer was pulled into tiebreaker of decider before avoiding a defeat at just the second match in the Tennis Masters Cup.

World number one Roger Federer kept in low status Tuesday as the two-time defending champion of the season-ending Tennis Masters Cup was pulled into tiebreaker of decider before avoiding a defeat at just the second match in Shanghai.

It took two hours and 17 minutes of the 24-year-old Swiss to defeat the in-form Croatian Ivan Ljubicic 6-3, 2-6, 7-6 (4), with a forehanded shot out of Ljubicic's reach for the tiebreaker win.

After Sunday's stumble win from Federer against Argentina's David Nalbandian, the last man having qualified for the elite eight-man field, nothing wrong from the tennis super star could be more shocking, even another rare fightback and a tiebreaker.

With all the embarrassments of backhand errors, weak returns and slow paces, Federer just repeated his sluggish form shown in Nalbandian's match, being broken twice in the second set after taking the first using an advantage of serving first.

Forced the decider, the superlative, who has compiled another outstanding season with an ATP-best 11 titles including two Grand Slam and a record four ATP Masters Series crown, should have shorten his work of Ljubicic in the ninth game before his two match points in hand were denied by the Croatian with some placement shots.

Ljubicic, who enjoyed his best season by winning two ATP titles in eight finals and broke into top ten for first time, then continually moved Federer to play close to the net and transferred errors from the Swiss to his own benefit before holding on to force tiebreaker.

With the victory, Federer saved his near-perfect record at the Tennis Masters Cup, increased his winning streak to 33, and extended his season-best match record to 79-3.

The Shanghai match was the first in six weeks for Federer, who has already clinched the world No. 1 year-end ranking for the second year in succession. He last competed in Bangkok, winning his 11th title of the season on October 2.

Ljubicic, the 26-year-old sensation of the late-season, had earned in place in Shanghai thanks to his autumn efforts,
including the indoor title win over the past month in Metz and Vienna as well as the final encounters in both the Masters Series Madrid and Paris two week ago.

The Croatian struck 10 aces and managed 36 winner, but else committed 5 double faults and 41 unforced errors in his defeat to Federer.

"It was very close match. I reel really upset because I felt I deserved this one," said Ljubicic at a post-match news conference.

"Today I felt like for the first time I was the better player on the court (against Federer), and that's why it feels frustrating because some shots just went out that they were not supposed to."

Before taking over control of the match, Ljubicic seemed to have problems moving during the first set.

"I had problems with him because he was playing just unbelievable," he said. "I think he played really high-class tennis in the first set, but I was also expecting his pace is going to drop because he dropped against Nalbandian, and I know he's not in top form physically.

"So I was just waiting my chances, and they came, and I took them."

"But I mean, Federer is not struggling. I just think that he's not top fit. He's not sharp as he usually is...I just tried to play my best tennis. It was almost enough. Unfortunately, it wasn't," added the Croatian.

The usually flawless Federer declined to agree with the negative comments on his performance, said: "I felt like this is exactly the match I expected."

"I expected a close match. I thought maybe he was even slightly the favorite because of what I've been going through the last few weeks. Obviously, I'm very pleased with the result because a win is a win no matter if it's two or three sets."

Federer called physiotherapist coming on court to treat on his sore ankle at the beginning of the third set, which raised worries that he might retire. And the Swiss denied that he remained on court trying to imitate the other five players who left.

"I did it for my well-being because I felt like my leg was starting to tighten up. Already I had that feeling against Nalbandian a little bit because maybe I'm compensating because of my injury."

He said "No" whenever asked whether to quit because of the injury, and also he emphasized that "it means very much to me (that I can play). It's also should show a message how much and how important this tournament means to tennis. For me, this is equaling like a Grand Slam."

The Swiss is building upon an imposing 14-1 record at the Masters Cup, with his only loss came to Lleyton Hewitt in the Shanghai 2002 semifinals.

Federer overcame the effects of the ankle ligament injury scare which threatened to keep him off the court at the Qi Zhong tennis center, and after American veteran Andre Agassi and second seed Rafael Nadal pulled out due to injuries on Monday, the Swiss has been left the only top-five player in the elite field.