Novak Djokovic knocked out of Cincinnati Open by Thiago Agustin Tirante

Novak Djokovic has suffered a shock second-round exit at the Cincinnati Open after battling severe heat in a three-set defeat by Argentina’s Thiago Agustin Tirante.

The 24-time Grand Slam champion was beaten 2-6 6-4 6-4 in his first competitive appearance since a semi-final loss at Wimbledon.

He visibly struggled with the oppressive humidity in Ohio and appeared to vomit during the gruelling encounter.

The former world number one even dropped to his hands and knees during a physically sapping contest that lasted two hours and 45 minutes.

Gruelling conditions take their toll

The Serbian veteran secured the opening set comfortably but began to physically fade as the match progressed.

He was forced to call for a medical timeout after surviving an exhausting 18-minute hold of serve in the second set.

Tirante eventually secured the decisive break at 4-4 in the deciding set before serving out the biggest victory of his career.

This is the best win of my career. I really did a good job inside the court.

The Argentine now faces Spain’s Martin Landaluce in the third round.

I managed very well the nerves of playing against a legend like Novak. Now I feel relieved.

Boulter exits women’s draw

In the women’s tournament, British number two Katie Boulter was eliminated following a straight-sets defeat to Wimbledon champion Linda Noskova.

The Czech player hit 10 aces and broke serve four times to secure a routine 6-3 6-3 victory.

Boulter had previously ended a five-match losing streak on the WTA Tour with an opening-round win against America’s Katie Volynets.