Two of Arsenal's summer signings scored to give the Gunners a 2-1 win over Olympiacos in their Champions League Group F clash at the Emirates Stadium.

Alex Oxlade-Chamberlain scored just eight minutes into his Champions League debut for the Gunners before fellow new boy Andre Santos doubled their lead midway through the first half. Olympiacos had responded well after going a goal down, and they pulled one goal back via David Fuster shortly before the half-hour mark.

Just two days before his 15th anniversary as Arsenal manager, Arsene Wenger once again looked on from the stands as he served the final game of his European touchline ban. As such, he watched yet another nervy and disorganised defensive performance by his players from on high.

The results means Arsenal are second in Group F with four points after two games, two points behind Marseille who beat Borussia Dortmund 3-0.

Despite attackers Theo Walcott and Gervinho being among several injured absentees for Arsenal, Wenger started with star striker Robin van Persie on the bench. Clearly with one eye on Sunday's North London derby away to Tottenham, Wenger started with Marouane Chamakh leading the line supported by Chamberlain and Andrei Arshavin.

The £12 million teenager started brightly and followed up his first Arsenal goal - in the Carling Cup win over Shrewsbury last week - with another strike after eight minutes. The former Southampton trainee took makeshift centre-back Alex Song's long ball on the chest, ran across the edge of the box and fired a classy low finish across goalkeeper Franco Costanzo. That strike sees Chamberlain - symbolically, perhaps - overtake team-mate Walcott as the youngest Englishman to score in the Champions League.

Olympiacos were unperturbed by going behind to that early strike, and they almost capitalised on some typical uncertainty from their hosts at a set-piece with a quarter of an hour on the clock. Mikel Arteta had to block Rafik Djebbour's close-range effort after Arsenal failed to deal with a corner and the Algerian fired the rebound into the side-netting.

Ernesto Valverde's side arguably had the better of the first half, even taking into account Santos's strike on 20 minutes. The Brazilian left-back hared down the left flank and hit a low ball across for Chamberlain but it was blocked by a defender and came back to him. The £6.8m signing from Fenerbahce reacted well to drill his shot under the keeper and ease the pressure on his team.

More defensive frailty at a set piece led to the home side conceding seven minute later. A short corner - a consistent feature for Valverde's side all evening - eventually saw a cross come in and it was met by Fuster, whose late run into the box was completely unchecked and he headed past the helpless Wojciech Szczesny with ease.

Moments later Szczesny was able to deny Djebbour from a tight angle, tipping the striker's shot over the bar before he also had to save Kevin Mirallas's near-post effort with his feet.

The Gunners emerged from their final team-talk held by assistant manager Pat Rice with renewed vigour. Chamberlain's effort in trying to lift Chamakh's neat through-ball over Costanzo was parried by the keeper before both the Moroccan and Arshavin had shots blocked inside the area after some good wing-play from their young team-mate.

The Gunners were looking fairly comfortable until midway through the second half when Olympiacos skipper Vasilis Torosidis cut in from the right and curled in a dangerous effort that rebounded off the bar with Szczesny not certain of reaching it.

The introduction of Aaron Ramsey and later Van Persie did much to stabilise the Gunners, however, and they go into Sunday's derby trip to White Hart Lane on the back of three wins in a week.

Tony Mabert - on Twitter @tony_mabert / Eurosport