World number one Roger Federer was forced to dig deep to keep his perfect record in Masters Cup round robin matches intact with a 4-6 7-6 6-4 win over a fired-up Andy Roddick on Tuesday.
American Roddick hassled and hustled Federer out of his comfort zone to win the first set and then had three match points in a thrilling tiebreak in the second, which the Swiss came back from 4-1 down to win 10-8.
The Wimbledon, Australian and US Open champion put himself in the driving seat to qualify for the semi-finals at the year-ending championship with his second Red Group victory when he sent an ace down the centre of the court after just under two and a half hours. Federer won the Masters Cup in 2003 and 2004, was losing finalist last year and has still not lost in 14 group matches at the tournament.