(CNN)Chris Froome will hold the yellow jersey going into the second week of the Tour de France but his Team Sky team was left to rue a missed opportunity in the team time trial Sunday.
Tour de France 2015: Chris Froome ends first week in yellow
Starting last in the 28km test, Sky led by five seconds at the foot of the final gradual climb to the finish in Plumelec only to concede first place on the stage to BMC Racing by a single second.
Froome and his teammates had to back off to wait for Ireland's Nicolas Roche, who could not keep up with their fierce pace, and the pain of defeat was plain to see at the finish.
"I don't have any words to explain my disappointment," Roche told Eurosport.
American Tejay Van Garderen of the BMC team has moved up to second place overall, but Froome has gained more time on his other major rivals.
Movistar's Nairo Quintana lost just three seconds as his team took third on the stage, but Alberto Contador conceded nearly half a minute with his fourth-placed Tinkoff-Saxo squad.
Defending champion Vincenzo Nibali was further back, 35 seconds down on BMC with his Astana team, and Froome has opened up a two minute 22 second advantage over the Italian.
"I didn't expect Nibali to have lost so much time by now," Froome told the official Tour de France website.
"To be totally honest, before the Tour I thought he'd be the one of my rivals who would have gained the biggest time in the first week."
The 2013 champion also had words of consolation for Roche and his teammates at missing out on the stage win.
"We would have loved to win today's stage but we can't be disappointed by our performance.
"At the end everyone has seen that Nicolas Roche was struggling a bit but this is the nature of team time trial.
"He has given so much before!. BMC did better than us and that's it."
The team time trial -- where the time of the fifth rider in each team is taken -- has proved a decisive factor in previous editions of the Tour de France, but the slim margins Sunday still leave the race open heading into the second week.
Ahead of the riders lie the Pyrenees -- with Tuesday's stage following a rest day.
There are seven mountain stages with five summit finishes set to test Froome and the other pretenders to the yellow jersey.
Van Garderen, 12 seconds down on the leader, is still upbeat about his chances of springing an upset.
"In the Pyrenees we'll see who is fit enough to win the Tour and in the Alps, we'll see who has the resources to win," he said.
"I'm pretty close to Froome but we'll only know in the third week who can do what. The Tour is a marathon. We aren't close to the end."
Contador, who trails Froome by one minute and three seconds, is bidding to do a rare double of Giro d'Italia and Tour de France in the same year.