Roger Federer recovered from his first-match nightmare to keep alive his hopes at the ATP Finals with a comfortable victory over Dominic Thiem.
Switzerland's Federer, knowing defeat would mean he would not advance from his group, beat the Austrian 6-2 6-3.
The six-time champion had slumped to a shock defeat by Kei Nishikori on Sunday but he cut down on his errors to win.
Next up for Federer on Thursday is Kevin Anderson, who beat Nishikori 6-0 6-1 earlier in the day.
More to follow.