PARIS (AFP) - Paris St Germain took one step towards silver-lining their disastrous league season by beating second division Amiens 1-0 Tuesday to book a spot in the French Cup final.

Substitute Yannick Boli scored the tie winner in the 78th minute of an otherwise forgettable encounter whose most exciting moment until then was a mass walk-off of the players in the 33rd minute.

PSG coach Paul Le Guen said: "It's amazing but we have to take things as they come. We'll try to recover well for Saturday (and the latest instalment of their survival battle against Saint Etienne).

"I'm not a dreamer, I've got my feet firmly on the ground - we have to concentrate now on Saturday."

Both teams left the park just after the half hour mark after a fan had thrown a tear gas canister on to the pitch, forcing a 10-minute stoppage.

Boli's goal came after he waltzed through the 2001 finalists' defence before beating Amiens 'keeper Benoit Benvegnu on a one on one.

PSG had keeper Jerome Alonzo to thank for avoiding extra time, and possible penalties, after he produced a superb last-gasp dive to thwart Fabrice Fiorese's well-taken first-time strike that was heading home.

Lyon face Sedan on Wednesday in the other semi-final.

PSG, French League Cup winners in March, are currently battling relegation, lying third from bottom with two games remaining against Saint Etienne and Sochaux.