The feud between tennis stars Jannik Sinner and Nick Kyrgios has reignited after the Wimbledon champion rehired the coach who unwittingly became embroiled in the Italian's doping scandal.

Nick Kyrgios has hit out at Wimbledon champion Jannik Sinner over his decision to re-appoint the fitness coach he split with after last year’s positive tests for banned substance clostebol.

Jannik Sinner has reappointed fitness coach Umberto Ferrara to his coaching team having previously dropped Ferrara during Sinner’s recent doping suspension.