Lleyton Hewitt will be out to cap another memorable year with victory in the final of the season-ending Tennis Masters Cup in Shanghai.

Hewitt advanced to the championship decider with a gripping 7-5 5-7 7-5 victory over gifted Swiss Roger Federer at The New Shanghai International Expo Centre on Saturday night.

The match lasted two minutes shy of three hours and the world No.1 must back up again for a best-of-five-sets encounter with fourth seed Juan Carlos Ferrero.

Ferrero beat his Spanish compatriot Carlos Moya 6-7 (6-8) 6-4 6-4 in Saturday night's first semi-final.

Hewitt had to save an incredible 17 break points to see off Federer, who had stormed through his three round-robin matches unbeaten.

Hewitt will be bidding for his fifth title of the year against Ferrero and success would add to his Wimbledon triumph in July and his second straight ATP Champions Race crown.

It would also double his weekly earnings of an already staggering $US700,000.

Hewitt admitted he didn't know how he was going to back up for the final.

"That's a good question. I am obviously a little bit tired at the moment," he said.

"To tell you the truth I don't know how I got through the last couple of matches. They were physically demanding. I think I went through the pain barrier in both.

"But Juan Carlos has had a couple of tough matches as well. We're both normally fit guys.

"It's going to be a grind."

Ferrero is chasing his third title of the year, from five finals, and will finish third in the Champions Race - behind only Hewitt and Agassi - if he can somehow conjure up an answer to stop Hewitt's relentless march to back-to-back Masters Cups.

Hewitt accounted for Ferrero in straight sets in the semi-finals of last year's edition of the season-ending championship in Sydney.

The 21-year-old Australian is 2-2 overall in career meetings with Ferrero.

Hewitt won 10 consecutive finals before dropping his last two, in Cincinnati in August and last week's Paris Masters.

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