Great Britain's Cameron Norrie will make his debut at the ATP Finals after Stefanos Tsitsipas withdrew injured from the event in Turin.

Norrie will take on Norway's Casper Ruud on Wednesday (20:00 GMT) and world number one Novak Djokovic on Friday.

The ATP said Greece's Tsitsipas had withdrawn with a right elbow injury.

Playing at the elite tournament, which features the year's eight leading male players, caps a successful year for Norrie, who won the prestigious Indian Wells tournament and became British number one in October.

He joins the event with one semi-final spot still available in his group after Djokovic booked his place in the last four with a clinical 6-3 6-2 win over Russian Andrey Rublev on Wednesday.

Djokovic said he was looking forward to facing Norrie in his final group match, adding: "Cameron Norrie deserves to be here. He was not 'lucky', he really worked his way to Turin with great wins."

Murray and Soares on brink of exit

Before Norrie plays his match, there will have been two other Britons in action at the event on Wednesday in the doubles.

Britain's Jamie Murray and Brazilian partner Bruno Soares were beaten in their second group match, losing 6-2 6-4 to Colombians Juan Sebastian Cabal and Robert Farah.

While they are not out mathematically with one round-robin match to play, it looks highly unlikely that they will advance to the semi-finals with their hopes resting on a complicated series of results in the group's remaining matches.

Briton Joe Salisbury and American Rajeev Ram, who beat Murray and Soares in their opener on Monday, face French duo Pierre-Hugues Herbert and Nicolas Mahut later in the day (17:30).