In an era when the top tennis players have become millionaires, it's customary to talk of competitors as gladiators, duelling it out for the ultimate prize, with gamesmanship the norm and little consideration for the loser.

But on a day when events off the court caused more discussion than those on it, an act of outstanding sportsmanship had the likes of Novak Djokovic wishing that he and his colleagues could show a bit more respect to opponents, even when in the heat of the battle.

It was the match between Rafael Nadal and unheralded American Tim Smyczek late at night on the third day that had everyone talking, for more reasons than one.

Nadal, despite suffering from stomach cramps and dizziness, found a way past the American in five sets, an effort that drew compliments from many players, all of whom have seen the Spaniard dig deep into his reserves on numerous occasions.

But it was the moment at 6-5, 30-0 in the final set that saw most reaction as Smyczek allowed Nadal to have another first serve, when a spectator shouted out during his initial attempt. Given the stage of the match, especially since it was the best performance of Smycek's career, it was an incredibly generous gesture, one that Nadal later described as "amazing".

Djokovic, who romped into the third round with a 6-0, 6-1, 6-4 win over Andrey Kuznetsov of Russia, was equally impressed. "I've seen the great gentleman gesture and sportsmanship from Smyczek in the last game," he said.

"This is something that is not very common in the sport today, where media and people generally emphasize on the rivalries, feisty, aggressive kind of approach to matches. It's nice to have something that is greater than sport itself, you know, the sportsmanship and fair play."

While instances of sportsmanship like that are relatively rare, Djokovic is one of those who has found the inner calmness and generosity to give his opponent a point at a crucial stage of a match.

Playing Czech Radek Stepanek at Wimbledon last summer, Djokovic had been awarded a let after an incorrect call, but conceded the point to his opponent, even though the match was at a tense stage, the pair tied 5-5 in the fourth set.

Defending champion Stan Wawrinka was another to praise the actions of Smyzcek. "I think it's great," said the Swiss, a 7-6, 7-6, 6-3 winner over Marius Copil of Romania.

"I think it was great for him to give back the point. You don't see it so many times and it's great sportsmanship."

Wawrinka said he hoped he would do the same thing as the American, in a similar situation, while John Isner, another second-round winner, agreed.

"It's very good sportsmanship on Tim's part," said Smyczek's compatriot. "I'd like to say I'd do it but in the heat of the moment you never know what you would do.

"I can't think off the top of my head but there have been a lot of cases where I've been given a first serve, which is a pretty big deal, and I think I've done it a few times. It doesn't happen a lot but it was good to see Tim do that."

Day three was the hottest of the tournament so far, with temperatures over 35C and humidity making life tough for all the players. Perhaps it was the heat that got to Andy Murray, too, as the Scot aimed a pretty clear shot at some of his detractors.

In what seemed a clear comparison with the positive reaction to Nadal's victory, Murray tweeted: "When I cramped and won in the US Open last year, I was a 'drama queen, unfit, needs to see a shrink, faker'. Weird."

It was an odd move from Murray, but one that shows that the unspoken Dunblane man has not forgotten the words of some people in the media who questioned his physical and mental state in New York last year.

Murray had suffered with all-over body cramps during his victory over Dutchman Robin Haase, with the pain setting in after just one hour, 45 minutes. For someone famously so fit and as one of the hardest workers on the Tour, it was an odd incident, but Murray showed great resolve to battle through.

Murray is due to play his third-round match against Joao Sousa of Portugal overnight, but one man who won't be in round three is Lleyton Hewitt. In his 19th Australian Open, the two-time grand slam champion led Benjamin Becker by two sets to love but was worn down in a final set.

"I haven't thought about the future," said Hewitt, though he did confirm that Davis Cup in March was next on his agenda.

Fifth seed Kei Nishikori dropped a set but beat Ivan Dodig of Croatia in a fourth-set tiebreak while No 8 Milos Raonic saw off American Donald Young in straight sets.