Andy Murray was certainly relieved to see the back of Ricardas Berankis and reach the last 16 of the Australian Open.
Although the No 3 seed beat the Lithuanian qualifier in straight sets, wrapping up a 6-3 6-4 7-5 victory in two hours and 12 minutes, the 25-year-old Scot admitted that his opponent had caused him serious problems.
Murray and the 22-year-old Berankis are regular practice partners and the reigning US Open champion said: "I was struggling. He was making me feel pretty uncomfortable on the court with his style.
"We know each other's games pretty well and we practise a lot together. He hits the ball very flat and these courts were playing quick today."
Berankis, the world No 110, broke his more illustrious opponent's serve once in each set and Murray accepted that he was not at his best.
He added: "I need to strike the ball better. My timing was off and I was leaving a lot of balls very short and allowing him to dictate some of the points. But hopefully it'll get better in the next round."
Last year's Olympic gold medallist and US Open champion will now face an exhausted Gilles Simon who could not have had a more contrasting passage into the fourth round.
He held off a magnificent comeback from French compatriot Gael Monfils to win 6-4 6-4 4-6 1-6 8-6.
The four hour 43 minute battle saw both players struggle physically, with Simon first receiving treatment in the third set for a quadriceps problem and later he also required a massage on his right forearm.
"I was almost dying at the end of the second set, it was already two hours long and I thought it would be difficult," Simon said.