"We can't get complacent," Chris Froome told reporters going into the 17th stage of the Tour de France on Wednesday.
"We're in a great position now but we've seen from the events this year just how quickly the race can change if we lose concentration for one minute."
Froome, the current jersey holder leads with one minute 47 seconds in the remaining four stages that penetrate deep into the Swiss Alps.
Cavendish pulls out
Wednesday's 17th stage of the Tour saw the riders climb 184km from Berne to Finhaut Emosson - an aptly named destination given that Finhaut means "high finish" and the route reaches almost 2,000 metres above sea level.
It will surely test Froome and his rivals to their limits.
The pressure proved too much for his compatriot Mark Cavendish who pulled out of the competition on Tuesday night to focus on his bid for gold at the Rio Olympics.
"The attacks aren't going to get any less, they could still keep coming," Froome added.
The 31-year-old Kenyan-born Briton is looking to win the Tour for a third time after claiming victory in 2013 and 2015.
On Wednesday he was able to bag extra seconds onto the clock, in a stage that was eventually won by Russian cyclist Ilnur Zakarin.
Colombia's Nairo Quintana was the big loser, struggling in the final 2km and giving up another 30 seconds to Froome, who pulled clear of all his main rivals except Australian Richie Porte.