(CNN) Novak Djokovic fell to the clay and looked to the sky — after three hours on court, the elusive French Open title was finally his at the third time of asking.

There were no tears like Roger Federer seven years before him, but this was a moment in history and the boy from Belgrade had become the first player to simultaneously hold all four grand slam titles since Rod Laver in 1969.

"I remember how difficult it was to arrive at that moment," Djokovic told CNN, reflecting on his 2016 triumph ahead of this year's tournament — which starts Sunday.

"The hours, commitment, and practice. Several years of not managing to make that final step. And then finally being able to make it and sharing that with the closest people in my life.

"It was an unforgettable moment."

Djokovic had fought back from a set down to beat an ascendant Andy Murray , calling upon all his steel and reserve, arriving at the pinnacle of his sport.

But while the outside world looked on and marveled, it would not prove easy to keep on climbing.

In the 12 months since, Djokovic has failed to add to that long-awaited 12th grand slam title, surrendering his world No. 1 ranking to Murray in the process.

"I am experiencing a little bit of a crisis, if you want to call it that," he admitted, having confronted what he calls "the other direction" after five years of success.

Which players have held all four Majors at the same time? Don Budge — 1938 Rod Laver — 1962, 1969 Novak Djokovic — 2015-16

Djokovic, who turned 30 earlier this month, believes that "finally being able to make it" in tennis' only clay-court grand slam may have diminished his motivation going forward.

"It was a lot of anticipation, expectations and pressure building up each year that I was coming back," he reflected. "It brought a lot of joy but also a lot of relief."

Murray acknowledged the magnitude of Djokovic's four consecutive grand slams at the time, telling the crowd "This has not happened for an extremely long time and will take a long time to happen again."

The Scot was resilient in defeat, stressing "This is his day today."

Not many would have predicted Murray would end the year world No. 1.

Typically, Djokovic would "bounce back" from big finals — whether victory or gut-wrenching defeat — "quickly recharging batteries" to return to the court.

He is the first to acknowledge how "very fortunate" he's been to have achieved so much, ever since "practically the beginning" of his career.

But this time something was different.

"There were so many emotions involved and so many things that were on the line," he said. "When I was able to achieve that, I was just so empty."

Which players have completed career grand slams and where? Fred Perry — 1935 Roland Garros Don Budge — 1938 Roland Garros Rod Laver — 1962 US Open Roy Emerson — 1964 Wimbledon Andre Agassi — 1999 Roland Garros Roger Federer — 2009 Roland Garros Rafa Nadal — 2010 US Open Novak Djokovic — 2016 Roland Garros

Djokovic needed time to recuperate and take stock of what he had achieved.

Instead, he was launched straight into the defense of his 2015 Wimbledon crown, before a trip to Rio de Janeiro for the Olympics.

And he simply couldn't cope, crashing out to world No. 28 Sam Querrey at the All England Club before falling — this time in tears — at the first hurdle to Juan Martin del Potro in the Olympic tennis tournament.

Photos: From nutritionists to "super coaches" Photos: From nutritionists to "super coaches" 2017 is turning out to be a bit of an annus horribilis for Novak Djokovic. Ahead of the French Open he teamed with Andre Agassi as the Serb looked for coaching guidance from the American tennis great. But Djokovic crashed out of the French Open after he was crushed by Dominic Thiem 7-6 (7-5) 6-3 6-0 in the quarterfinals. Hide Caption 1 of 13 Photos: From nutritionists to "super coaches" In May 2017, Novak Djokovic parted ways with his entire coaching team in a bid to rediscover his "winning spark." Scroll through the gallery to see who has been part of the Serb's coaching team over the years. Hide Caption 2 of 13 Photos: From nutritionists to "super coaches" Nikola Pilic (1999-2003) – A French Open finalist in 1973, Nikola "Niki" Pilić went on to become the first captain to win the David Cup trophy for three different nations. The Croatian coached a teenage Djokovic at his tennis academy in Oberschleissheim, Germany. Hide Caption 3 of 13 Photos: From nutritionists to "super coaches" Dejan Petrovic (2004-2005) – Djokovic was coached by Dejan Petrović from the age of 16, moving over 200 places up the rankings into the ATP top 100 inside a year. Petrović, an Australian-born Serb, also coached 2008 French Open winner Ana Ivanovic from 2014 to 2015. Hide Caption 4 of 13 Photos: From nutritionists to "super coaches" Riccardo Piatti (2005-2006) – Italian tennis coach Riccardo Piatti divided his time between working with Djokovic and former world No. 3 Ivan Ljubičić. Despite only coaching Djokovic until the Serb was 18, Piatti claimed he always knew his protege was destined for greatness because he "battled so hard." Hide Caption 5 of 13 Photos: From nutritionists to "super coaches" Marián Vajda (2006-2017) – Former Czechoslovakia tennis player Marián Vajda coached Djokovic for over a decade, guiding his charge to 12 grand slam titles. The two parted ways in May 2017 as Djokovic sought "shock therapy" and a fresh direction ahead of the French Open. Hide Caption 6 of 13 Photos: From nutritionists to "super coaches" Mark Woodforde (2007) – Alongside Vajda, Djokovic worked with Australian 12-time grand slam doubles champion Mark Woodforde during the spring hard-court season in 2007, honing his volleys and net play. Hide Caption 7 of 13 Photos: From nutritionists to "super coaches" Todd Martin (2009-2010) – With his first major under his belt -- the 2008 Australian Open -- Djokovic turned to American former world No. 4 in the summer of 2009. The pairing ceased when the Serb lost his opening match of the Miami Masters after Martin had tried and failed to rejuvenate the Djokovic serve. Hide Caption 8 of 13 Photos: From nutritionists to "super coaches" Gebhard Phil-Gritsch (2009-2017) – Djokovic hired German fitness coach Gebhard Phil-Gritsch (R) in the spring of 2009 having identified conditioning as a weakness in his game. The two worked together until May 2017. Hide Caption 9 of 13 Photos: From nutritionists to "super coaches" Igor Četojević (2010-2011) – The most transformational figure in Djokovic's illustrious career was arguably not a coach but a nutritionist. Dr. Igor Cetojevic instructed the Serb to undertake a gluten-free diet, immediately alleviating his breathing problems and bringing spectacular results. Hide Caption 10 of 13 Photos: From nutritionists to "super coaches" Boris Becker (2013-2016) – Djokovic appointed six-time grand slam champion Boris Becker head coach in December 2013, citing him as a "true legend." It would become a fruitful partnership, with Djokovic winning six major titles in three years. Hide Caption 11 of 13 Photos: From nutritionists to "super coaches" 'The time of our life' – They ended their arrangement in December 2016, capping a tumultuous year for Djokovic, who released a statement saying: "I will make all future decisions." Becker, in the aftermath of the announcement, posted on Twitter: "Thank you! We had the time of our life." Hide Caption 12 of 13 Photos: From nutritionists to "super coaches" Andre Agassi (2017) – When Djokovic ended his longstanding relationship with Vajda in May 2017, it appeared he was ready to go alone. But ahead of his French Open title defense, the 30-year-old turned to yet another so-called "super coach," approaching Agassi later that month and citing his "tremendous respect" for the American. Hide Caption 13 of 13

"Superman never loses," they lamented in his native Serbia, bemused and shaken by their hero's new-found fallibility.

But it kept getting worse.

And when he was sent packing from this year's Australian Open in the second round by unheralded wildcard Denis Istomin — departing at the earliest stage of any grand slam since 2009 — Djokovic was haunted by doubts he would ever be the same again.

"It's all part of the sport," he shrugged. "I'm feeling much better now than I was maybe three or four months ago. I'm excited to go back to Paris again, obviously.

"It's been a year and it feels like it was yesterday."

Djokovic with tears in his eyes after losing against Juan Martin Del Potro at Rio 2016.

'The King of Clay'

It's no coincidence Djokovic won that elusive French Open crown in the year nine-time winner Rafael Nadal withdrew with a left wrist injury in the third round.

The Spaniard, dubbed the "King of Clay," has only ever lost two matches at Roland Garros.

Djokovic has nothing but respect for his rival as he looks ahead to a possible meeting in Paris.

"It's quite incredible that he's going for his 10th title," he enthused. "Rafa has been so dominant there.

The world No. 2 has of course enjoyed his own preeminence on the tour — not least in Melbourne where he is tied with the great Roy Emerson on six men's grand slams — but few have ever mastered a surface like Nadal.

"He's been playing some extraordinary tennis this year, very high quality," says Djokovic. "He's definitely going to be the player to beat. He always is and he always was on clay especially in Roland Garros.

"It's going to be an exciting tournament."