DAVID O'Leary has warned Aston Villa to expect a "heck of a battle" when they meet Wanderers in the semi-finals of the Carling Cup.

The Villa boss is excited at the prospect of a Millennium Stadium final against Arsenal, the club he served for 18 years as a player.

But he was taking nothing for granted after Villa's 2-1 victory over Chelsea when he said: "It would be brilliant for me if we could get through to Cardiff and play the club who did so much for me.

"I've never been to that stadium and it would be fantastic if it was Arsenal we were playing.

"But first of all we know that Bolton will give us a heck of a battle. It will be tough."

The draw was kind to Wanderers. Following the quarter-final victory over Southampton, Sam Allardyce had been anxious to avoid a two-leg tie against Arsenal.

"We've had our days against Arsenal in the past but two on the trot -- home and away -- would have been a big test for somebody like us," he said. "Better to meet them in the final in a one-off when anything can happen."

Buoyed by already having drawn at Villa Park when the teams met in the Premiership in October, Allardyce now has the chance to avenge the penalty shoot-out defeat Wanderers suffered at Villa's hands in the FA Cup semi-final at Wembley in 2000.

Chelsea went into the Villa Park tie reeling from the shock Premiership defeat by Wanderers and were rocked by a stunning strike by Juan Pablo Angel.

Joe Cole equalised, but Gavin McCann sealed the win.