Imperious Novak Djokovic declared that he was "a completely different player" from the first half of this year after he beat France's Jeremy Chardy 6-3, 7-5 to roll into the Shanghai Masters third round on Tuesday.
The rejuvenated Serbian second seed has now won all 12 matches against Chardy and this victory was never in doubt.
The 31-year-old Djokovic had to contend with a more stubborn Chardy in the second set, before the world number three's superior shot-making won through in 83 minutes.
The 14-time Grand Slam champion missed six months of competition in 2017 and had elbow surgery in February.
But he has burst back to form and fitness since the summer, winning Wimbledon, the US Open and the Masters 1000 Cincinnati in a terrific run, and says he is back close to his best.
Djokovic, who is eyeing Rafael Nadal's number one ranking, said: "I haven't won too many matches the beginning of the year.
"After the surgery I was not managing to play my best, and that has changed, so obviously the more you win, the more comfortable and more confident you feel on the court."
The Serb will play either Italy's Marco Cecchinato or South Korea's Chung Hyeon next -- he lost to both during his darker days in the first half of the year.
"I think I'm a completely different player than I was in first five, six months of the year," he said.
"Hopefully the outcome can be different as well."
In the absence of the injured Nadal, holder Roger Federer is the top seed in Shanghai and the Swiss great starts his campaign on Wednesday against Russia's Daniil Medvedev.
Nikoloz Basilashvili won his sixth straight match Tuesday, beating Denis Shapovalov 6-2, 6-2 in the first round.
Basilashvili, who won the China Open last week and has moved up to a career-high ranking of No 23, never faced a break point on his serve. The Georgian earned his first victory at the tournament after qualifying in 2015 and 2017.
On Sunday, Basilashvili upset fourth-seeded Juan Martin del Potro in the final in Beijing. Earlier this year, he became the first Georgian man to win an ATP title when he won in Hamburg - playing as a qualifier.
Basilashvili will next play fourth-seeded Alexander Zverev in the second round.
While, Daniil Medvedev, who upset Kei Nishikori to win the Japan Open on Sunday, struggled but beat Chinese wild-card entry Zhang Ze 3-6, 7-6 (6), 6-4 in the first round.
Medvedev has won all three finals he has appeared in this year and did so by beating the home favorite. Besides beating Nishikori in Tokyo, he defeated Alex de Minaur in Sydney and Steve Johnson in Winston-Salem, North Carolina.
Earlier, French qualifier Benoit Paire upset 15th-seeded Pablo Carreno Busta 6-3, 6-4.
roger set for defence
Roger Federer warned Novak Djokovic and his other Shanghai Masters rivals on Tuesday that he was in prime condition even as another long season approaches its climax.
The 37-year-old Swiss has been carefully managing his schedule in recent years, cutting out the clay-court segment of the season since 2017 to wring the most out of his ageing body.
It appears to be working and the 20-time Grand Slam winner opens his defence of the Shanghai Masters this week in ominously good shape.
The world number two played in a victorious Laver Cup campaign in Chicago two weeks ago, following his surprise last-16 defeat to the Australian John Millman at the US Open.
"The good thing is after feeling good in practice I played a good Laver Cup, have had also some rest after the US Open," said Federer.
The Swiss great's prime threats in Shanghai are likely to come from world number three Djokovic — who is in fine form — and fourth-ranked Juan Martin del Potro.
World number one Rafael Nadal, beaten by Federer in last year's final of the Masters 1000 showpiece, is absent with injury.
Del Potro, who was hindered by cold and flu in losing Sunday's China Open final to unseeded Nikoloz Basilashvili, said in Beijing last week that he was running on empty.
Not so Federer, it seems, who is seven years older than the Argentine.
"I feel like I'm where I want to be," Federer said.
"I know that this is where I could be playing a lot of tennis, depending on how I play." Reflecting on his 2018, which included winning the Australian Open and several weeks back at world number one, Federer said: "I have actually been very successful when I played.
"I didn't play many poor matches, to be quite honest. There is only maybe a couple that come to my mind and I have been injury-free for over a year now." Federer, who is chasing his fourth title this season, will face either Chinese wildcard Zhang Ze or feisty Russian Daniil Medvedev in his opener.