The Pole clocked a time of 5 hours 52min 53sec for the 231 kilometres route in Spain’s mountainous Basque Country.

Lotto Soudal's Tony Gallopin of France finished runner-up, while last year's winner Bauke Mollema of The Netherlands came third to earn bronze for Trek-Segafredo.  

Victory for Kwiatkowski secured his third one-day race success of the season having won the Strade Bianche and Milan-San Remo, events both held in Italy, in March.

He was helped considerably by team-mate Mikel Landa of Spain, whose late surge allowed Kwiatkowski to stay in contention with rivals Gallopin, Mollema and Team Sunweb’s Tom Dumoulin of The Netherlands going into the last kilometre.

It set up a final sprint which Kwiatkowski won convincingly.

"You could see Mikel Landa playing his crucial role in the end and I could go for the sprint easily," Kwiatkowski was reported as saying by Cycling News.

"I'm very thankful to Mikel that he waited in the group in the front.

"Today was just amazing.

"With the team spirit, we believed that we could win the race."

Rio 2016 Olympic gold medallist Greg Van Avermaet of Belgium finished in eighth place.

The BMC Racing rider was 38sec back.

The opening stage of the Tour de Pologne also took place today with Bora-Hansgrohe’s Peter Sagan of Slovakia sprinting to victory on his first competitive outing since being disqualified from the Tour de France.

The double world champion completed the 130km route in Kraków in a time of 2:56:16.

Orica-Scott’s Caleb Ewan of Australia was the next across the line, followed by Team Sky’s Danny van Poppel of The Netherlands.

Sagan was thrown out of the Tour de France after appearing to elbow one of his main rivals, Great Britain's Mark Cavendish, on the fourth stage.

It caused the Dimension Data rider to fall heavily in the roadside barriers, leaving him bloodied.

Cavendish ended up pulling out of the event having broken his right shoulder in the crash.

Following his win today, Sagan told Cycling News: "It’s very nice to be here, and get a lot of support and energy from the people here.

"Slovakia is close by.

"The Slovakian and Polish fans have been amazing.

"I felt a lot of positive energy in the race."

Tomorrow's second stage sees riders undertake a 142km route from Tarnowskie Góry to Katowice.

The women’s WorldTour race in London was another event held today with the United States' Coryn Rivera coming out on top after a sprint finish.

The 24-year-old Team Sunweb rider clocked a time of 1:29:04 for the 66km race, made up of 12 laps of the 5.5km circuit through the British capital's city centre, in wet conditions.

Cervélo-Bigla Pro Cycling's Lotta Lepistö of Finland finished second, while Canyon-SRAM's Lisa Brennauer of Germany came third.

The Netherlands' Marianne Vos was fourth, while compatriot and last year's champion Kirsten Wild was fifth.

"I'm absolutely elated - they were not the best conditions but when you've got a goal, you've got to commit and get after it," Rivera told BBC Sport.

"I knew I was in the right place and just had to time my sprint correctly.

"It's a very long sprint so it's a bit deceptive, but I went at the right time and pulled it off."

The men's race is scheduled to take place tomorrow.