Arsene Wenger is confident youngster Kieran Gibbs will thrive in an unexpected run at left-back in the first team.

With Gael Clichy set for an extended spell on the sidelines following a stress fracture to his lower back, 20-year-old Gibbs will start against AZ Alkmaar in Wednesday night's Champions League clash at the Emirates Stadium.

It is a role familiar to the England Under-21 international, whom national team manager Fabio Capello admits is in his thoughts ahead of next summer's World Cup finals.

Despite the disappointment of a high-profile slip which proved costly during the second leg of the Champions League semi-final against Manchester United, for the most part Gibbs has not looked out of place when filling in for Clichy - the Frenchman having been missing for the closing months of last season, also because of a back problem.

While Wenger would have preferred to give Gibbs more experience in smaller doses, such as the Carling Cup, the Arsenal manager believes the young defender is more than ready to make the step up.

"I was very comfortable to have a solution to rest Clichy when it was needed and play Gibbs. Now suddenly there is a huge stress on Gibbs to play in every game," he said.

"Capello and England will be happy because they want him to play of course, but it is still a blow for us to lose Clichy."

Wenger, though, declared: "I have no doubt about the quality of Gibbs, and I have said that many times."

The Gunners kept up the pressure on leaders Chelsea and Manchester United with a 3-0 win over north-London rivals Tottenham, and could move into the last 16 of Europe's elite club competition with victory on Wednesday night.

Arsenal have a match in hand on both Chelsea and United, who clash on Sunday, while the Blues travel to the Emirates Stadium at the end of the month.

Russian playmaker Andrey Arshavin believes the current 11-match unbeaten run is evidence Arsenal's young side have shown they can compete for top honours.

Wenger is content to see such determination, and believes, channelled correctly, it can only be positive.

"I am happy with the confidence," Wenger declared.

"However, you do not have to confuse confidence with arrogance.

"The confidence comes from that we are in this job to try to win, and I am very happy that the players believe they can do it."

AZ boss Ronald Koeman will relish the challenge of frustrating Wenger once again - but admits his side face a difficult task.

The Dutch coach has yet to lose a contest with the Gunners boss.

Indeed the former Netherlands defender - who scored the goal which won Barcelona the 1992 European Cup at Wembley - masterminded a famous result when in charge of PSV Eindhoven on his last visit to the Emirates Stadium during March 2007, when a late goal from Alex, now at Chelsea, saw the Gunners crash out 2-1 on aggregate.

However, Koeman, 46, accepts the challenge ahead with AZ - who are struggling to recapture the form which saw them win the Eredivisie title last season - is completely different.

"Of course, I remember one moment with PSV, when we played out a 1-1 draw, which was enough to beat Arsenal at that time," he said.

"However, we are now a few years later.

"This game is the most difficult one of all six group games we will have to play."