Young rival's cheeky message for Rafa Nadal after career-best win

Rafa Nadal's training partner delivered a hilarious message to the 21-time grand slam champion after his match at Acapulco.

Stefan Kozlov, who was involved in a bizarre incident with a BMW last week, was in the middle of a training session with Nadal at the Mexican Open.

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However, due to an injury and withdrawal from Maxime Cressy, Kozlov was chosen as the lucky loser main draw entry.

The 130th ranked American lost in the Mexico Open qualifying, but gained the call up and was to face Grigor Dimitrov.

And the American said Nadal was super excited for the 24-year-old.

"I was playing a practice set with Rafa ... he breaks his string, goes to his bag. I just happen to check my phone for whatever reason," Kozlov said after the match.

"I just had an intuition and then I have 20 text messages ... they're like 'get over here'.

"I dropped all my stuff. I told Rafa, he's got a big smile on his face. He's super excited for me, he knew I was No.1 lucky loser.

"I got over here and I had about 30 minutes to get ready."

Footage of their training session showed Kozlov rushing to leave the court with Nadal wishing him luck.

Kozlov could be heard on the phone asking: "Who do I play?"

Stefan Kozlov's hilarious message to Rafa Nadal

Amazingly, Kozlov ended up defeating the former World No.3 Dimitrov 7-6, 5-7, 6-3 after suffering from severe cramps in the second set.

And Kozlov wrote a cheeky message to Nadal following the best win of his career.

"Rafa, sorry for stopping practice today," he wrote on the camera lens, as is tradition for tennis players at some tournaments.

Amazingly, Kozlov could face Nadal in the next round if the Spaniard defeats American Denis Kudla.

"Today I was totally expecting not to be playing," said Kozlov, adding that he would have retired if he had failed to hold his first service game in the third set against Dimitrov.

"Now I've got the biggest win of my career and I'm about to play Rafa Nadal."

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