ST MAIXENT-L'ECOLE, France, July 25 (Reuters) - Jan Ullrich threw down the gauntlet to Lance Armstrong in Friday's 18th stage of the Tour de France on the eve of the 49-km time trial which is expected to crown the overall winner.

The German, winner of the Tour in 1997, forced the American overall leader into action when he took part in an intermediate sprint early in the 203.5-km stage from Bordeaux to St Maixent l'Ecole.

Points standings leader Robbie McEwen of Australia won the sprint, held at 50 km, but Ullrich was second and Armstrong third.

As a result, Ullrich grabbed a four-second time bonus while Armstrong took two seconds. The Team Bianchi rider now trails four-times champion Armstrong by 65 seconds overall at the end of a stage won by Spaniard Pablo Lastras.

The time gain may have been minute but was a way for Ullrich to taunt his rival before the final showdown.

"It's Jan himself who made the decision, but with a side wind it was a little risky," said his team director Rudy Pevenage.

"Jan was in the front, he saw the sprint could suit him and seized the opportunity to take a few seconds.

"I was a little surprised for it was a bold gamble. But he really believes in his chances," he said.

Armstrong played down Ullrich's move as irrelevant.

"It's not important. I don't think that the Tour will be won or lost for two seconds," he said.

RENEWING HOSTILITIES

But the American, who bids for a record-equalling fifth Tour victory, said he was concentrating on Saturday's stage.

"The most important thing is tomorrow of course. I'm staying calm and confident. In the last four years I always rode pretty good in the last time trial.

"I'm going to keep cool and ride my race," he said.

Everybody expected the 148 riders left in the peloton to take it easy before the time trial between Pornic and Nantes in which Ullrich will try to overhaul Armstrong.

But the pace was extremely lively throughout and the average speed, at 49.938 kph, was the second fastest for a stage in Tour history.

While the leading duo were unexpectedly renewing the hostilities one day early, 16 riders broke away. Their lead quickly grew to reach 22:30 at best.

The leading group was down to eight riders with 15 km to go when Spain's David Canada broke away.

France's Carlos Da Cruz counter-attacked in the final kilometre and seemed ideally placed but was outsprinted by Lastras on the line.

"We were all exhausted but I probably wanted the victory more than the others for my mother, who died four months ago," Lastras said.

It was the fourth stage victory by a Spaniard in this Tour.

Ullrich's unexpected sprint favoured McEwen's plans as the Australian took the points standings green jersey off compatriot Baden Cooke.

McEwen also got the better of Cooke and German Erik Zabel in the sprint for 17th place at the front of the main group, who finished some 23 minutes behind Lastras.

The race for the green jersey, which McEwen won last year, will be decided on the last day on the Champs-Elysees. McEwen leads Cooke by two points.

Colombian Santiago Botero, one of the pre-Tour favourites after beating Armstrong in a time trial last year, did not start the stage.

Updated on Friday, Jul 25, 2003 11:20 am EDT