Annabel Croft has claimed that Andy Murray will face his toughest ever first-round match at a Grand Slam when he takes on Nick Kyrgios at the US Open.

The British number one was drawn against the 20-year-old Australian on Thursday.

Murray has beaten Kyrgios in all three of their previous encounters, but Croft still expects the former champion to be severely tested.

"It will be the pick of the first-round matches for sure, but I think it's a really tough one," she told Sky Sports News. "Actually I would almost say it's the toughest first round that Andy might ever have had in a Grand Slam to be honest.

"You have to remember he has beaten him every time he has played him, but I still think it's a tough draw because Andy always admits he's a little bit nervous in the first rounds of a Grand Slam.

"In all the draws that I have seen Andy have in the course of his career, I would say this is one of the toughest ones, but I would still pick him to go through."

Murray reached the quarter-finals of last year's US Open before losing to Novak Djokovic.