Australia's John Millman has been forced to retire from his first-round match at the Mexico Open after suffering an eye injury in bizarre circumstances.

Millman sustained the injury against Marcos Giron in Acapulco, when the American was leading 7-6 (7-3), 2-0.

In what seemed to be an innocuous incident at first, Millman appeared to hit a ball into his right eye when he tried to deflect a return from Giron following a failed attempt at serving.

The ball caught the frame of his racquet, before making contact with his eye as he walked towards the baseline.

Millman immediately dropped his racquet and collapsed to the court while holding his hand over his right eye.

Loading

He eventually withdrew from the match, leaving Giron to advance to the next round.

Millman — ranked 80th in the world — was playing in Mexico after reaching the semifinals of the Delray Beach ATP Tour event last week.

Meanwhile, Daniil Medvedev continued his pursuit of the number-one ranking with a 6-3, 6-4 win over Benoit Paire to move into the second round in Acapulco.
  
The 26-year-old can overtake Novak Djokovic and move into the top spot if he wins the title in Mexico.

He will play either Alex Hernandez or Pablo Andujar in the next round.

The likely biggest challenge for Medvedev in Mexico could be Rafael Nadal, who beat the Russian in last month's Australian Open final.

Nadal opened his Mexico Open account with a 6-3, 6-2 win over Denis Kudla.

The Spaniard has won three titles in Acapulco (2005, 2013 and 2020) and will play against Stefan Kozlov in the next round.

ABC/AP