Novak Djokovic has won the other three Grand Slams of 2021 - can he complete the set at the US Open?Dates: 30 August-12 September Venue: Flushing Meadows, New YorkCoverage: Daily radio commentaries on BBC Radio 5 Live Sports Extra/BBC Sport website and app, with selected live text commentaries and match reports on the website and app.When Novak Djokovic won the 2016 French Open, and became the first man since Rod Laver to hold all four Grand Slams simultaneously, he danced to the Gypsy Kings near the Arc de Triomphe.
His attempt to win all four Grand Slams in the same year was ended by Sam Querrey at Wimbledon a few weeks later.
Five years on, the world number one has another chance. An even better chance, having already won the Australian Open, the French Open and Wimbledon in 2021.
If the 34-year-old Serb can add the US Open, which starts in New York on Monday, he will be the first man since Laver in 1969 to complete a clean sweep of the Grand Slam singles titles.
It would be the greatest achievement of his career, and arguably the greatest achievement in the history of men's tennis.
"I can't wait. Honestly, I'm very motivated to play my best tennis," Djokovic said, before Tuesday's first-round match with Danish qualifier Holger Rune.
"I have to hit one ball at a time, as they say - have a guiding star. I don't need to put any additional pressure to what I already have, which is pretty big from my own self and from people around me.
"But I thrive under pressure, as well. I've done that many times in my career. I'm a big tennis fan, fan of history. I have this chance, and I'm going to try to use it."
Djokovic is also aiming for a 21st Grand Slam title to overtake Roger Federer and Rafael Nadal for the outright men's record, but he still has Steffi Graf, Serena Williams and Margaret Court to catchDjokovic's year started with a ninth Australian Open title in Melbourne, despite a stomach muscle injury which he thought might end his tournament.
But his most significant week of the Grand Slam year, thus far, came at Roland Garros in early June.
On the second Monday, he recovered from two sets down to beat Italian teenager Lorenzo Musetti in the fourth round.
On the Wednesday, Djokovic beat Matteo Berrettini in four sets after a 15-minute wait at 23:00 BST as Court Philippe Chatrier was cleared of spectators to meet a Covid curfew.
On the Friday, despite being 5-0 down in the first set, he condemned Rafael Nadal to only his third ever defeat at Roland Garros. It was one of the most brutal clay-court matches of recent times, and yet on the Sunday Djokovic was able to recover again from two sets down as he beat Stefanos Tsitsipas to win a second title in Paris.
With the French Open pushed back seven days, there were only two weeks before Wimbledon. Djokovic won there, too, dropping only two sets to join Laver, Nadal, Roger Federer and Bjorn Borg as the only men in the Open era to win both tournaments in the same year.
And so to New York, where Steffi Graf completed the calendar Grand Slam in 1988, but Serena Williams fell two wins short in 2015.
Williams lost in the semi-finals to world number 43 Roberta Vinci, who was competing in her first Grand Slam singles semi-final. The American insisted she felt no pressure, but it would have been impossible not to, given the attention and excitement generated by her quest in New York that year.
Laver's triumph came 19 years before Graf's. The Australian recalls staying in the apartment of his good friend, actor Charlton Heston, that fortnight.
"I knew that I was heading for the Grand Slam, so if I could win this particular tournament then I'm sort of set in gold - and that was a nice feeling," Laver told BBC Sport.
"I didn't try to explain it to anyone that I was going for the Grand Slam - that just puts more pressure on you. I kept it to myself. I was ready for it. I was fit, I had practised hard."
Rod Laver is the only man in the Open era to complete a calendar Grand SlamThe 24-hour news cycle makes such serenity impossible these days, but Laver thinks Djokovic should try to put the prize out of his mind.
"If he's putting pressure on himself, saying he really wants to win this, then all these things are going to come into play," says the 83-year-old.
"If you get to that level, you start thinking more and more and more. If he wants to win it, I would think the best thing is to get all that behind you, and don't talk about it."
Until his defeat by Alexander Zverev in the semi-finals of the Olympic event in Tokyo, Djokovic was on course for a Golden Slam: a term coined in 1988 when Graf won all four Grand Slams and a gold medal in Seoul, on tennis' return to Olympic competition.
The Serb spoke afterwards of "abnormal pain and exhaustion" and has not played any tournaments since.
A calendar Grand Slam in the men's game seemed far-fetched when Djokovic, Nadal and Federer were all in their prime. But that should not for one moment devalue the achievement of winning 28 consecutive best-of-five-set matches, on three different surfaces in four different time zones.
As his coach Goran Ivanisevic said at Wimbledon, Djokovic never knows when he is beaten.
"Even when he's not playing the best tennis, he's winning. So imagine when he's playing the best tennis, is impossible to beat him," said 2001 Wimbledon champion Ivanisevic.
"For me, Novak is the best ever. He's writing history. He's going to do it in the US Open. I strongly believe he's going to do it - he's going to win all four in one year. Then I think story's over.
"He's like in the movies. You have to kill the guy 27 times, and still he gets up."
