Belgian Wout van Aert raced to victory in the Tour of Britain on Sunday while Spaniard Carlos Rodriguez made a strong charge to win the hilly eighth and final stage in Wales.
Norway's Tobias Halland Johannessen of Uno-X was three seconds behind Van Aert in second, while Australian Damien Howson (Q36.5), with the same time, was third.
Ireland's Ryan Mullen finished 47th overall in the general classification, 13:35 off the lead.
Van Aert had begun the final day with a slender three-second lead after narrowly failing to win Saturday's seventh stage.
Rodriguez, of Ineos Grenadiers, started the stage 39 seconds down before attacking on the mountain climb of Bryn Du some 50 kilometres from the finish and led the rest of the way.
The 166.8-km stage was temporarily neutralised at the 83-km mark due to a motor vehicle collision on the course that was unrelated to the race.
Stage eight travelled from picturesque Margam Country Park to the finish line in the shadows of Caerphilly Castle in South Wales, with a gruelling double ascent of Caerphilly Mountain.
"It feels great," Van Aert said. "We've had such an amazing week as a team, starting off with five stage wins in a row. It’s pretty incredible.
"From then on it was a lot of pressure on us in this race, but we managed to control every stage, basically. So we’re super proud, especially to finish off that teamwork.
"It was a super tough stage with the course this year. The weekend was really decisive and we went really all in for the GC.
"Today the climbs were a bit longer, which is tricky for me especially compared with riders like Rodriguez and [Stevie] Williams who are 20kg lighter than me.
"I had to stay calm and trust my team-mates. I really had to think a lot in that final."
