King Keown is back

"The experience will do them so much good," said Wenger. who is likely to stick to his mix-and-match policy for the semi-finals.

"Without the more experienced players I am not sure they would have won. We were under a lot of pressure in a very physical game. We needed the right blend of players and we had that. We had to be totally focused to get through the tie."

Stack continues to grow in stature and after Albion's initial assault was repelled, Arsenal took the lead when a cross from Lauren took a wicked deflection and looped high in the air.

Kanu hardly had to lift his 6ft 5ins frame off the ground to head goalwards. Keeper Russell Hoult parried his first effort but had no chance when the Nigerian stroked the rebound home. Stack saved from Hulse early in the second half but then Hoult was left exposed again. A back pass from Thomas Gaardsoe was not only unnecessary but also struck far too hard.

Hoult, with one eye on Aliadiere, panicked with his clearance and saw it strike the young Frenchman before rolling neatly into the Albion goal for the second.

Game over - and Wenger was able to bring on Fabregas and had the luxury of giving a taste of quarter-final football to 20-year-old Jerome Thomas as Arsenal comfortably saw out time.

Stack said: "They're big games for the youngsters - playing Wolves and West Brom is all part of gaining experience and putting yourself on the map as a player.

"You work day in and day out in training - but it's nice to prove you're capable to the fans when you get your chance.

"I'd be disappointed not to play in the next game - but to get into the semis is a fantastic feat for such a young side. It speaks volumes for our academy." Wenger will wait for the semi-final draw before deciding his team. He said: "It is difficult to predict what I will do for the semi-finals. I will always select a team that I think can win a particular match. It will depend on injuries and the fixtures we have at the time."

One thing's for sure. The future looks bright.

"We are a club on the run," Wenger said.

Meanwhile, Bolton, Arsenal's Premiership opponents on Saturday, clinched a place in the last four with a 1-0 win over Southampton thanks to an injury-time goal by Henrik Pederson.

But in January they will be without influential skipper Jay-Jay Okocha, who will be preparing for the African Nations Cup with Nigeria - and that has enraged Sam Allardyce.

The Bolton boss said: "I can't have my skipper for one of the most crucial games in the history of this club. one that could get us to Millennium Stadium. That, for me, shouldn't happen. It is an outrageous situation."