TOUR de France leader Michael Rasmussen struck a potentially fatal blow to his rivals’ hopes by winning stage 16 from Orthez to the Col d’Aubisque.

The Dane launched a blistering attack in the final kilometre, beating the American Levi Leipheimer by 25 seconds.

More importantly he increased his overall lead over Alberto Contador by 34 seconds.

Barring accidents this will give him a 3:10 advantage over the Spaniard going into Saturday’s time-trial, Contador’s last realistic chance of knocking Rasmussen, who because of his painfully thin build is nicknamed "the chicken", off his perch.

Hopes of a scandal-free day were banished when the Italian Cristian Moreni of the Cofidis team tested positive for testosterone, but with the peloton still in a state of shock following Alexandre Vinokourov’s positive drug test on Tuesday, Spain’s Carlos Sastre tried to steal the headlines by launching an early attack.

Sastre started the stage sixth overall and at one stage had slashed the Rasmussen’s lead to just two minutes, but he was hauled back on the Aubisque.

With nine kilometres left Contador attacked and temporarily lost Rasmussen, but the Rabobank rider’s more measured style saw him drag his way back up to the explosive Spaniard, before he ditched him and Leipheimer with less than a thousand metres to go.

Cadel Evans of Australia lost more time on the leading duo and is now 5:03 behind Contador, but remains third overall, 56 seconds ahead of Leipheimer.