Lleyton Hewitt encountered a conundrum in yesterday's fourth-round match as he came up against a man just as stubborn as himself. He eventually solved the puzzle set by Spain's tenacious 23rd seed David Ferrer by the simple expedient of getting even stubborner than usual. Which, as anyone in tennis will tell you, is very stubborn indeed.
The 25-year-old Australian, making his eighth consecutive appearance at Wimbledon, is currently exhibiting his best form since winning the title here four years ago, and his eventual 6-4, 6-4, 4-6, 7-5 victory kept him on course for a possible semi-final meeting with another flourishing young Spaniard, Rafael Nadal.
Hewitt's immediate task, however, is to do what Andy Murray failed to do yesterday and find a way past the quirky Cypriot, Marcos Baghdatis.
As Hewitt acknowledged, Baghdatis has had a bit of a strange tournament so far, having struggled in his first round against Alan MacKin and then beaten Britain's lone star in straight sets.
"I think everyone's been put on notice of the kind of talent and flair that he possesses out there when he plays at his best," Hewitt said. "It won't be an easy one."
Nor was his match yesterday on a sweltering No 1 Court where he punctuated his performance with meaningful looks and gestures towards his watching wife Bec - formerly of TV's Home and Away, now simply away from home a lot - and his coach Roger Rasheed.
"It's always nice to get into the last eight,' he said. "Sometimes you don't have to play your best tennis to get there, you have just got to try and find a way to win against certain different opponents."
Ferrer, one of three Spaniards through to the fourth round, soon made it clear that the Australian was going to need to draw upon all of his indomitable resources to progress in temperatures that were in the mid-90s.
Having gone 5-1 up in the first set, Hewitt was forced to cede the next three games before pushing on to win 6-4. The next set went with serve all the way to 4-4, although Hewitt had to survive three break points on his fourth service game as Ferrer, trading shots with him from the baseline, began to play with greater aggression. The last of the break points was saved thanks to an ace which was initially called out, but then given through an overrule by the umpire.
Ferrer, who had already sent his racket cartwheeling on a couple of occasions, as well as picking up a warning for an audible obscenity, appeared to question the call, implying that Hewitt may have prompted it with a protest.
Many-tongued rumour had it that Hewitt had told his headband-bearing opponent to get his hair cut - but the Australian dismissed that idea.
"I think he thought that I persuaded the umpire for an overrule, but the umpire had already overruled straight away. I just asked him if he didn't hear it." That was certainly how it sounded on court.
Despite seeing the second set evade him, Ferrer was far from done. He had recovered from two sets down to win his second-round match, and he soon made it clear that he intended to reproduce that feat as he continued to apply pressure to the Hewitt serve, forcing the Australian to survive another two break points at 3-4, and finally breaking through at 5-4 up as Hewitt gave up the set point on a double fault.
It had developed into a match the intensity of which was only mitigated by the amplified sound from somewhere off court of Maria Sharapova making the kind of noises which, if one heard them in the street, would prompt a call to the police.
As Ferrer raced to a 3-0 lead in the fourth, he was beginning to position himself in a curious statistical position, given that Hewitt had lost in eight of his previous nine Grand Slam tournaments to the eventual winner.
Such unlikely fancies were soon ground down, however, as Hewitt clawed his way back into the match to draw level. The Ferrer racket took a few more airborne trips, and when the No 6 seed broke to 6-5 with an acutely angled backhand and another roar of "Come on!" it was time for the Spaniard to vamos. Hewitt accepted afterwards that his motivation at SW19 may be more profound than some of his opponents.
"Maybe it means more to me than some of the other guys, especially some of the clay courters," he said.
"That comes with having had success here, and all the Australian winners before me, and the tradition that Wimbledon has back in our country as well."
Meanwhile, he seems set on extending his own Wimbledon tradition of unyielding commitment. He will take a lot of budging this week.