London, UK, 17 November 2017 | tennis.com.au

Australia’s John Peers and Finnish teammate Henri Kontinen are back in the semifinals of the season-ending ATP Finals in London.

After winning the prestigious title last year, Peers and Kontinen again advanced to the last four after French duo Nicolas Mahut and Pierre-Hugues Herbert were forced to withdraw.

Herbert injured his back during Thursday morning’s practice session and later announced his withdrawal; the team was replaced by alternates Raven Klaasen and Rajeev Ram.

I'm starting crossing fingers and toes as Herbert left practice suddenly after missing a serve. Mahut did look a bit surprised. Hope it's nothing.

— Carole Bouchard (@carole_bouchard) November 16, 2017

Peers and Kontinen went on to beat Klaasen and Ram – a repeat of the 2016 final in London – 2-6 6-1 [10-8].

They finished group play with a 2-1 record, behind the unbeaten duo of Ryan Harrison and Michael Venus.

Peers and Kontinen will in the semifinals face the top-finishing team from the other round-robin group; at the moment that’s likely to be Lukasz Kubot and Marcelo Melo, who have won both their round-robin matches in straight sets.

Kubot and Melo face Jamie Murray and Bruno Soares – currently with a 1-1 record on Friday in London.