Wimbledon: Defending men's champion Novak Djokovic beats Kwon Soon-woo in opening match

Defending champion Novak Djokovic says the possibility of not being allowed to contest another Grand Slam for 11 months is "motivation" for Wimbledon after his quest for a fourth successive title began with a four-set victory.

Serbia's former world number one, 35, has said he would rather miss out on competitions than get a Covid vaccine.

The 20-time major winner missed the Australian Open following a row over his vaccine status, while proof of vaccination is also currently required to gain entry into the United States.

Djokovic has been banned from entering Australia for three years following his deportation in January, although was told by former Prime Minister Scott Morrison that he could be allowed back sooner under the "right circumstances".

But should nothing change, it would mean that after Wimbledon Djokovic would be unable to play at a Grand Slam until next year's French Open.

"I guess that motivates me more to try to make the most out of this tournament," the six-time Wimbledon champion said.

"There's not much time after Wimbledon before the US Open. I'm hoping some things can change and that I'll be able to go and compete.

"I would want to. But it is what it is at the moment. My thoughts and attention is here."

Djokovic said the situation at the Australian Open had been "challenging emotionally" but that he was "very pleasantly surprised" by the positive reception he received from the Wimbledon crowd on Monday.

The top seed overcame South Korean world number 81 Kwon Soon-woo 6-3 3-6 6-3 6-4 under the Centre Court roof as he aims win a seventh title at SW19, which would take him one behind Roger Federer's men's record.

As tradition dictates, defending men's singles champion Djokovic began proceedings on Centre Court as the Championships returned with full capacity crowds on Monday.

The world number three is the favourite to retain the title once again in the absence of top-ranked Daniil Medvedev - banned following Wimbledon's decision to deny entry to Russian and Belarusian players following Russia's invasion of Ukraine - and the injured Alexander Zverev.

He overcame a spirited opponent to back up that billing and set up a second-round meeting with Australian Thanasi Kokkinakis.

It was 24-year-old Kwon who landed the first blow to the delight of an excitable Centre Court crowd, stunning the top seed with a break to 15 and again surrendering just a single point as he employed impressive variety to consolidate a 3-1 advantage.

But Djokovic settled in, breaking back before another allowed him to serve out the opening set with a five-game streak.

Undeterred, Kwon, who won his sole ATP title to date in Astana last September, responded with a break for 3-1 in the second set and impressively saw off three break points from a 0-40 deficit to hold in the following game on his way to levelling the contest.

Encouraged by the crowd as he continued to apply pressure in the third, the South Korean was unable to clinch a break point in the fifth game - allowing Djokovic to strike late on and retake the lead.

They proved crucial moments, as Djokovic, having saved a break point in the opening game, eventually asserted himself in the fourth set.

A single break proved enough for him to come through this tricky first-round encounter, extending his victory streak at Wimbledon to 22 matches.

It also means Djokovic becomes the first player, man or woman, to record 80 singles wins at all four Grand Slam tournaments.

Spanish teenage sensation Carlos Alcaraz continues to attract attention as one of the sport's most promising young talents, having demonstrated his huge potential by reaching the second major quarter-final of his career at Roland Garros in May.

With two ATP 1000 titles from Miami and Madrid also to his name in 2022, along with a 33-4 win record, there are high expectations on his return to Wimbledon as the fifth seed.

It is, however, only his second tour-level tournament on grass, and he faced a tough challenge against the experienced Jan-Lennard Struff under the Court One roof before eventually prevailing in five sets, 4-6 7-5 4-6 7-6 (7-3) 6-4.

Having lost the first and third sets, Alcaraz showed great composure to keep himself alive in the contest by winning seven of the final eight points in a must-win fourth-set tie-break.

With a potent serve and the crowd fully behind him, the 19-year-old world number seven clinched the decisive break in the ninth game of the decider to ensure he equalled the second-round appearance he achieved on his Wimbledon debut last year.

Polish seventh seed Hubert Hurkacz, a semi-finalist last year, suffered a shock five-set loss to Alejandro Davidovich Fokina.

Hurkacz, who beat Daniil Medvedev and Roger Federer on his way to the last four in 2021, blew a 7-4 lead in the final-set tie-break as he fell to a 7-6 (7-4) 6-4 5-7 2-6 7-6 (10-8) defeat.

The 25-year-old was instantly in trouble against Davidovich Fokina, ranked 37th in the world, as the Spaniard took the opening two sets and had three match points in the third, before Hurkacz fought back to give himself hope of completing a fine turnaround.

He was serving for the match at 5-4 ahead in the fifth set, but lost his serve, and then appeared in control of the final set tie-break.

However, Davidovich Fokina won six of the last seven points to win in three hours 28 minutes and set up a second-round tie against Jiri Vesely of the Czech Republic.

"Really I don't know how I won this match," Davidovich Fokina said. "This win means a lot to me. I had a lot of matches against players in the top 10 and have not won, but here on grass I've proved I can beat anyone."

Meanwhile, 2017 finalist Marin Cilic was forced to withdraw from the tournament without hitting a ball after testing positive for Covid-19.

Elsewhere, Norwegian third seed Casper Ruud progressed with a 7-6 (7-1) 7-6 (11-9) 6-2 victory over Spain's Albert Ramos-Vinolas and American 2018 semi-finalist John Isner fought back to win in five sets against France's Enzo Couacaud, prevailing 6-7 (6-8) 7-6 (7-3) 4-6 6-3 7-5.

Later on Monday, Italian 10th seed Jannik Sinner beat three-time Grand Slam champion Stan Wawrinka 7-5 4-6 6-3 6-2.