Dominic Thiem stretches to return a forehand against Kei Nishikori on Thursday. Photo: John Walton/PA via AP

LONDON – Dominic Thiem claimed his first win of the week at the ATP Finals as he beat Japan’s Kei Nishikori 6-1 6-4 to stay mathematically alive at the O2 Arena on Thursday.

The Austrian, beaten by Kevin Anderson and Roger Federer in his opening two round-robin matches, dominated throughout against Nishikori, who can no longer reach the semi-finals.

Thiem now needs South African Anderson to beat six-time champion Roger Federer comfortably in the day’s second singles to have a chance of reaching the last four.

That scenario would leave Thiem, Federer and Nishikori on one win each – meaning second place in the group would be decided by sets percentages and then games percentages.

Nishikori could not qualify in that scenario after suffering a 6-0 6-1 defeat by Anderson followed by another heavy defeat at the hands of Thiem on Thursday.

Federer, who bounced back from his loss against Nishikori to beat Thiem in his second match, effectively needs to win one set against Anderson to reach the semi-finals at the tournament for the 15th time in 16 appearances.