IN the blink of an eye, it was almost over.

He might enjoy a healthy lead as this year's Tour de France approaches its final few stages, but Chris Froome was afforded a timely reminder of the fragility of that advantage as he descended into Gap yesterday.

While Rui Costa raced to a solo stage win up ahead, Alberto Contador was attacking Froome so hard the Spaniard came off his bike on the way down the Col de Manse – a road that has seen its fair share of Tour drama over the years – and the Team Sky rider had to veer off into the verge to avoid going over himself. Froome accused the Spaniard of riding dangerously and admitted he feared it would be worse. "One second you can be going for the finish and about to win, and the next moment you're lying in a ditch somewhere with broken bones," he said. "Nothing is guaranteed in cycling."

Contador, a two-time Tour winner of the Tour, responded by saying he has no interest in a runners-up spot this year and that was clear in the risks that he took in his attempts to wrestle the yellow jersey from Froome yesterday.

"He was pushing the limits too far and he took himself down in front of me which also put me as risk," Froome said. "I had to go off the road for a second to try and get around him. I didn't really come off, I just had to reclip into my bike and get going again. I don't think it was necessary to take those kinds of risks."

Contador, who seemed unhurt after crossing the line, was unapologetic and promised there would be more attacks. "It is not a motivation to scare the others but sometimes you have to do it. I will continue," the 2007 and 2009 champion said.

A uneventful stage 16 – dominated by a 26-strong breakaway – had been notable only for a train delaying the peloton at a level crossing until they came to the category two Col de Manse. After the breakaway split and Costa races clear to win comfortably, the real drama took place when the overall contenders began their ascent. Contador and his team-mate Roman Kreuziger took it in turns to attack Froome, and at one point succeeded in dropping Richie Porte to isolate the yellow jersey, although the Tasmanian soon got back to his team-mate – something that would prove critical after Froome's near-miss.

This was the road where Joseba Beloki crashed on melting tarmac while battling Lance Armstrong for the yellow jersey in the 2003 Tour, effectively ending his career at the highest level. Beloki had been invited back by the Tour but declined, still haunted by the incident, and although there was no repeat – authorities even doused the road with water to avert the risk of the surface breaking up in the heat – there was a clear reminder of the dangers.

"I knew this was the descent where Beloki crashed and I was laying off a little, trying to take it easy, but at the same time I had to keep in touch with Saxo-Tinkoff pushing the limits," Froome said.

While Contador picked himself up and Froome got back on the tarmac, Bauke Mollema, Froome's closest challenger four minutes and 14 seconds back and 11 seconds ahead of Contador, was racing away in a group with Nairo Quintana. Porte led Froome back but there were further flashpoints – Froome gesturing to Contador to contribute to the chase as he followed – and the Spaniard giving Quintana an ironic thumbs up for not slowing after their crash.

While tempers had been frayed, Froome was glad to escape without any lasting scars. "The road surface was quite bumpy all the way down and there were a few little wobbles," he said. "I was happy to get to the end without doing any damage."

However, Sky know this is likely only the start as Contador and others try to find a way to claw back time on Froome with the days ticking down before Paris. "I saw a kitchen sink being thrown at us," Porte said. "It made sense that they were going to attack. It was a hard start and we expected they would try something on that last climb and descent. They have to try something now and hats off to them. They were good today, the Tour's not over yet and they are going to keep riding aggressively."

Froome is ready for that, but is hoping his rivals can keep a cool head as the race hots up. "I think teams are starting to get desperate," he said. "They are going to take uncalculated risks."