Roger Federer [Images] will need to clear a towering obstacle if he is to get his hands on the World Indoor Tournament crown this weekend.

That hurdle happens to be the 1.96 metre tall Mario Ancic and the duo will lock horns for the second time in Saturday's semi-finals, with Federer looking to make amends for his 2002 first-round defeat at Wimbledon.

"I lost to Ancic quite a while ago but I never won a set against him. It will be interesting," said the Basel FC fan.

"This is the position where I like to be in, semi-final days and this is when I usually raise my game and I hope I can do it again this week."

Federer has already described this week's event as strange because it is one of a handful of tournaments he competed at this year in which he is not the defending champion.

"Here is one of the few ones that I didn't win so something quite bizarre this pressure not being there (to defend points)," said Federer.

Having played at the Ahoy arena for five of the past six years, Federer is determined to add his name to the circular billboard of champions that can be seen around centre court.

The popular Swiss lost only six times in 2004, the first of those coming in the Rotterdam quarter-finals against British number one Tim Henman.

It must have been a strange experience for a player who went on to capture 11 titles, including three of the four Grand Slam crowns last year. Impressively, he achieved all that without the services of a coach.

This year, however, the script has not gone according to plan and Federer is not willing to suffer any more slip ups.

He has already lost his Australian Open title, losing in the semi-finals despite holding a match point against eventual champion Marat Safin [Images], and feels he has to make amends.

"It (losing) was a good story for the season as I'm third in the (ATP Champions) race and I definitely want to get up there so I need good results and might as well start at Rotterdam," said Federer.

Unlike his previous three opponents, Federer is aware he will have to face the bullet-like deliveries of Ancic and an attacking game plan.

However, having built an almost indestructible aura around himself since his loss to Ancic, Federer said he will be ready.

"I don't want the pressure off my shoulders as I always want to win. As long as you win, you're confident and it's the best way to play tennis," he said.

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