Novak Djokovic earns comfortable win over David Goffin at ATP World Tour Finals

Novak Djokovic has claimed his third straight victory on the bounce at the ATP World Tour Finals by overcoming David Goffin in straight sets at the O2 in London.

The 12-time Grand Slam champion was scheduled to meet Gael Monfils in the round-robin clash, but the Frenchman withdrew from the tournament on Wednesday evening due to a rib injury.

Goffin - Monfils's replacement - failed to cause an upset on the court today as he relinquished the first set in 37 minutes after dropping serve twice.

The second set was much the same as Djokovic raced to a 5-2 lead before converting his second match point to wrap up the win and secure a spot in the semi-finals of the season-ending tournament.