Geraint Thomas won the 70th Criterium du Dauphine in France to give Team Sky their sixth victory in the race in the past eight years.
The Welshman, 32, finished one minute ahead of nearest rival Adam Yates, who won the final stage.
Thomas said he took each day as it came during the event, but now realises he has "won a massive race".
The double Olympic champion finished with an overall time of 24 hours 43 minutes 12 seconds.
Despite having to "chase back" after his tyres were punctured during the final stage, he said he grew in confidence as the race wore on.
"I knew I had about one minute 20 seconds to lose on Yatesy so at 200m to go, when they started sprinting for the win, I was relieved," said Thomas.
Yates, 25, finished the seventh stage in three hours 51 minutes 34 seconds with Thomas in fifth, 19 seconds behind.
Frenchman Romain Bardet came third overall while Britain's Tao Geoghegan Hart finished 13th.
In a double success for Team Sky, they also won the team event, finishing seven minutes 18 seconds ahead of Team Emirates.