MIAMI (AFP, REUTERS) - Novak Djokovic remains on course for a record seventh Miami Open tennis title, but the world No. 1 was made to fight all the way to the last 16 in a 7-5, 4-6, 6-1 victory over spirited Federico Delbonis on Sunday (March 24).
The Serb is hoping to eclipse Andre Agassi's six ATP crowns in South Florida over the next week and although the 31-year-old endured some shaky moments at Hard Rock Stadium, he still possessed enough quality during the key moments to see off the battling Argentinian.
But women's defending champion Sloane Stephens was sent packing after a 6-3, 6-2 loss to Germany's Tatjana Maria in the third round.
The 2017 US Open champion and world No. 6 had no answer to Florida-based Maria's slices, chips and lobs and suffered a second consecutive early exit after losing her first match in Indian Wells to Swiss qualifier Stefanie Vogele.
Against Delbonis, Djokovic was not happy with letting a 5-2 advantage slip in the first set and became furious with himself as the second squirmed from his grasp.
He will need to tighten up his game if he is to reach Sunday's final, with Roberto Bautista Agut waiting in the fourth round after the Spaniard defeated Italian Fabio Fognini 6-4, 6-4.
"Federico is playing well and it was really close at the start of the third set," said Djokovic who smashed 36 winners compared to 24 from Delbonis - whose excellent performance was punctuated with five double faults and a 67 per cent success rate on his first serve.
"It was an exciting match and I am just pleased that I managed to hold my nerve," he said. "I got down on myself and Federico started swinging."
Djokovic had looked impressive in the second-round win over Bernard Tomic and the Serb continued his decent form by immediately imposing himself on the Argentinian.
The world No. 83 struggled to contain Djokovic, who was serving superbly and an early break saw the 15-time Grand Slam winner gain control.
Djokovic moved 5-2 ahead but after he missed a set-point opportunity on Delbonis' serve, his game deserted him and suddenly, the South American had a spring in his step.
Delbonis had opportunities to steal ahead, yet calling on all his experience and mental resolve, the Serb was able to hold firm and take the opener.
Delbonis continued to be competitive and brilliantly hit back after being broken for 3-1, which saw Djokovic hurl his racquet to the ground in utter frustration and receive a warning from the umpire.
The Argentinian was hitting the ball superbly, especially from the back of the court, and another brilliant winner handed him two break opportunities which were taken when Djokovic sprayed long.
The world No. 1 was getting incredibly frustrated, yet credit to Delbonis who stayed calm and served out confidently to force a decider, something which looked beyond him midway through the opening set.
He could not keep the pressure on, however, and when Djokovic managed to get 3-1 ahead, this time there was no way back for the 28 year-old from Azul who rightly received an ovation from the centre-court crowd for his monumental efforts.
In other women's matches, Latvian 11th seed Anastasija Sevastova lost 1-6, 6-2, 6-3 to Kazakh Yulia Putintseva, while 25th-seeded American Danielle Collins went down 7-5, 6-1 to China's Wang Yafan.