Chris Froome has sent an ominous message to the rivals bidding to snatch the Tour de France leader’s yellow jersey off him, saying: “I’m getting stronger”.

The Team Sky leader has a 12-second advantage over Tejay van Garderen (BMC Racing) after nine stages of the Tour, with his other major contenders trailing by at least one minute.

Alberto Contador (Tinkoff-Saxo) is 1min 3sec back, Nairo Quintana (Movistar) 1min 59sec adrift and the defending champion Vincenzo Nibali (Astana) 2min 22sec behind.

Asked about his position on Monday’s first rest day in Pau and before Tuesday’s first Pyrenees stage, the 167-km route from Tarbes to La Pierre-Saint-Martin, Froome compared himself favourably to his condition in 2013, when he won the 100th Tour.

“I think I’m in quite a different position than I was two years ago,” said Froome, who crashed out of the 2014 Tour. “I came into the race extremely ready two years ago. I’d won pretty much every race building up to the Tour and I did feel as if once I got past the halfway mark in the 2013 Tour that I was almost just hanging on to the finish.

“This year I feel as if I’ve come in much fresher, a lot more mentally prepared and I feel as if I’m getting stronger in this year’s race. Now it’s up to other teams to put the pressure on us. This is the heart of the race now. This is where all the action’s going to be happening, we’re going to see who has done their homework, who has got what in the mountains. This is where the real race in yellow truly starts.”

The route from the start in Utrecht, through the Netherlands, Belgium and northern France, was expected to challenge Froome, but he has thrived and is relishing the high mountain stages where the yellow jersey is won.

Froome, the second Briton to win the Tour after Sir Bradley Wiggins in 2012, said: “Coming into this race there was a lot of last year still in the back of my mind. This first week was really one of the biggest concerns. The big thing was not to actually lose any of the time to any of the contenders.

“It is the first mountain top finish. Everyone’s going to be looking at this as a gauge as to how things are going to go the next two weeks. It’s a very important stage, but I’m very grateful that I’m in this position now, that I’m not trying to make up time on someone else.

“To actually be in this position, to have gained quite substantial amounts of time on a lot of my big rivals, this is the dream scenario at the moment. I really just have my team to thank for that.”