The 34-year-old, Tour runner-up in 2007 and 2008, will likely become the first Australian winner of cycling's most prestigious race after turning a 57-second deficit to Andy Schleck (Leopard Trek) into a one minute 34 second advantage in the foothills of the Alps.

Evans entered today in third place overall, almost a minute behind Andy Schleck and four seconds adrift of Frank Schleck, but his superior ability against the clock told.

Evans finished in 55 minutes 40 seconds, two minutes and 31 seconds quicker than Andy Schleck, who will surely now settle for second place for a third successive year.

Barring a freak accident or illness, tomorrow's 95km 21st and final stage from Creteil to the Champs-Elysees in Paris will see Evans crowned Tour champion.

Tony Martin (HTC-Highroad) won today's stage in the foothills of the Alps in 55mins 33secs, seven seconds ahead of Evans, with three-time Tour champion Alberto Contador (Saxo Bank-SunGard) third in 56:39.

Ireland’s Nicolas Roche did not have his best ride, finishing in 114th place on the satge, six minutes and 29 seconds behind Martin.

The Ag2r la Mondiale rider has slipped to 26th in the overall standings.

The 21st stage to Paris is traditionally a celebratory procession for the overall contenders, with the sprinters battling for supremacy on the Champs-Elysees, where Mark Cavendish (HTC-Highroad) will target a third successive win and a first points classification's green jersey.

Provided he negotiates the final route safely, a first Tour title for Evans should be secure.

Evans was beaten in the 2007 Tour by Contador by 23 seconds and in 2008 by Carlos Sastre, but he has consistently performed in 2011 and convincingly claimed the title.

The former world mountain bike champion gained time on the Schleck brothers with every revolution of the pedals.

Andy Schleck, who was second to Contador in 2009 and 2010, must now face up to taking second place on the podium once again after one day in the yellow jersey following yesterday's final day in the Alps.

Frank Schleck will likely step onto the podium for the first time, but France's Thomas Voeckler (Europcar), who was overtaken by Andy Schleck in the yellow jersey yesterday, will have to settle for fourth place, 3:20 behind Evans.

Contador is set to end a difficult defence of his title in fifth place and lies 3:57 behind entering tomorrow's final day.

World and Olympic time-trial champion Fabian Cancellara set the early pace today, clocking 57:15, but was soon succeeded as race leader by Richie Porte (Saxo Bank-SunGard), Belgium's Thomas de Gendt (Vacansoleil) and then Martin.

The German's time was apparently unassailable and with the stage seemingly wrapped up, the focus turned to the overall fight.

Due to his overall position at the start of the day, Evans was third last to start, with Frank Schleck and Andy Schleck starting at three minutes intervals behind him.

Evans began quickly and continued to set a steady pace and reached the first time check, which came after 15km, in 20:33.

Andy Schleck covered the same distance 36 seconds slower, seeing his lead on the road reduced to 21 seconds.

Midway through the stage Evans had cancelled out his time deficit to Andy Schleck and with every pedal stroke he moved further into the lead.

By the second time check, 15km from the finish, Evans was 1:42 seconds ahead of Andy Schleck and in the maillot jaune by 25 seconds.

As Evans passed the third time check, 7km from the end, two seconds behind Martin's time, his overall lead stretched to almost a minute.

The Australian eased off in the finale so as not to take any unnecessary risks and finished second only to Martin on the stage, with Contador (Saxo Bank-SunGard) 1:06 behind the German in third.

Andy Schleck came in 2:38 behind Martin in 58:11 as his quest for the Tour title remained elusive.

Frank Schleck finished in 58:14 and place 19th.

Team Sky's Edvald Boasson Hagen clocked 57:43 to place 12th, despite requiring a bike change in the final 5km.

The leading Briton today was David Millar (Garmin-Cervelo), who finished in 59:14 to place 32nd.

Geraint Thomas rolled around in 59:57, while his Team Sky colleague Ben Swift completed the route in 1:02:47.

Cavendish, wearing the points classification leader's green jersey and seeking to seal the prize in Paris tomorrow, clocked 1:04:08, 6:53 behind.

Cavendish was docked points in each of the last two days after finishing behind the permitted cut-off time in the final two Alpine stages.

But his total of 280 points was safe today and he will carry a 15-point advantage over Jose Joaquin Rojas (Movistar) into tomorrow's final stage.