Spanning two days and nearly four hours of match time, it is little wonder Novak Djokovic regarded his fourth-round Wimbledon win over Kevin Anderson as one of the toughest matches of his career.
The defending champion had to fight back from two sets down on Monday to level it up before bad light stopped play and he returned to No.1 Court on Tuesday to win the decider 7-5.
Anderson provided stiff opposition and had a look at a couple of break points himself in the fourth game of the fifth set, but the South African served back-to-back double faults as he was broken to hand Djokovic the chance to serve for the match - with the Serb gleefully obliging, before reflecting on his narrow escape.
"I find that this was one of the most difficult matches I've played at Wimbledon, maybe my career," Djokovic told BBC Sport.
"At times I was helpless with my returns. I found it very difficult to read his serve.
"It was high-quality tennis in the fifth set. It was frustrating at times, but I managed to go through and that's what matters."
The world number one will face ninth seed Marin Cilic in the quarter-finals and hopes the experience of such a difficult match will stand him in good stead.
He added: "I was two sets down, to come back and win in five definitely gives me great satisfaction and confidence ahead of the next challenge.
"I congratulate Kevin for a great effort. It would not be undeserved if he had won this match."