Furious Medvedev slams umpire’s chair with racket TWICE as Russian explodes during ATP Cup clash (VIDEO)

Russian tennis ace Daniil Medvedev courted controversy as he slammed the umpire’s chair with his racket twice during a heated encounter with Argentina’s Diego Schwartzman in the ATP Cup quarterfinals in Sydney.

The hotheaded Medvedev won the match 6-4 4-6 6-3, but was forced to regain his composure after clashing with his opponent Schwartzman and umpire Mohamed Lahyani during a particularly tense second set.

ATP Cup: Russia into semifinals after Medvedev edges ill-tempered clash with Argentina’s Schwartzman

Medvedev was first warned for exchanging words with Schwartzman after the Argentine broke the Russian's serve, which forced Lahyani out of his chair to intervene.

But Medvedev then reacted furiously when in conversation with Lahyani as he was told that Schwartzman had not been handed a sanction over the incident, with Medvedev twice striking the Swedish umpire’s chair with his racket.

The 6ft 5in Russian was docked a point over the incident – although some online felt he should have been defaulted from the match altogether.

Medvedev, 23, ultimately recovered his composure to win the third set, and later suggested his belligerence may have been down to the effects of sleep deprivation.  

“I think I slept five hours in the last two days, with the jetlag coming from Perth,” Medvedev said on court after his hard-fought win.

“So I was feeling like sh*t, but I was happy with the win.”

Russia faced Argentina at Sydney’s Ken Rosewall Arena on Thursday – having last played Norway in the group stage on Tuesday, more than 2,000 miles (3,200km) away in Perth on Australia’s west coast.

After Medvedev averted a meltdown to take control in Sydney, team captain Marat Safin praised his ability to regain focus – something he has struggled to do in the past.

Medvedev famously clashed with fans in New York on his run to the US Open final last year, while he was also accused of melting down in his defeat to Rafael Nadal at the ATP Finals in London at the end of the season.  

READ MORE: Medvedev melts down as Nadal storms back to win ATP Finals clash

The win from world number five Medvedev on Thursday gave Russia an unassailable 2-0 lead in the tie against Argentina, after teammate Karen Khachanov had earlier seen off Guido Pella in more straightforward fashion, 6-2 7-6 (7-4).

Russia will play either Serbia or Canada in the semifinals in Sydney on Saturday, which should at least allow Medvedev a good night's sleep before then.  

Hosts Australia will contest the other last four encounter against either Spain or Belgium.