Tennis can be an incredibly frustrating sport, even for the most accomplished men's player of all time. Novak Djokovic let his anger show with a heated rant during practice with coach Andy Murray. Djokovic is currently preparing to kick off his campaign at the Madrid Open.

Novak Djokovic was left furious with himself in an angry Madrid Open practice session with coach Andy Murray before his opening match. The Serbian tennis legend locks horns with Italian world No.44 Matteo Arnaldi in the second round on Saturday at the Spanish clay-court event.

Novak Djokovic has opened up on his partnership with Andy Murray, admitting it’s “not easy” for the Brit to coach him. Murray joined his old rival’s team during the off-season and is joining him at this week’s Madrid Open, where Djokovic is looking to bounce back from a brutal opening-round defeat in Monte-Carlo.