Arsenal’s young Ox in the box masks familiar defensive lapses

Arsenal 2 Olympiakos 1

If only the whole story of last night for Arsenal had been as sweet as the moment when Alex Oxlade-Chamberlain burst past the opposition's defence to become the youngest English Champions League goalscorer in the club's history.

In that one instant, when the teenager – just 18 years and 44 days old – opened the goalscoring for Arsenal against Olympiakos, the home fans were transported back to a time when Arsène Wenger unearthed young gems such as these as a matter of course. The young Englishman from Southampton is a bright young prospect but he cannot cure all the club's ills.

This was a valuable three points for Arsenal but there is no point them kidding themselves it was straightforward. After Oxlade-Chamberlain and then Andre Santos had given them a two-goal lead within 20 minutes they lost their way in familiar fashion. The Greek champions were pushing right until the last few seconds for a second goal that they arguably deserved.

After two games of the Champions League, Arsenal have four points, more than Manchester United and Manchester City combined, but there are still reasons for concern. They struggled badly in defence at times, only getting a grip in the second half following a bombardment before the break that threatened to overwhelm them.

By the end they could give thanks for Oxlade-Chamberlain whose Champions League debut was particularly assured given his youth. With Wenger serving the last game of his Uefa touchline ban it fell to his assistant Pat Rice to put the teenager's performance into perspective. The former Arsenal captain may be famously conservative but even he pronounced that Oxlade-Chamberlain's development was "bodes well for England".

Rice said: "From the Arsenal supporters' point of view, they are going to be seeing a lot of this boy. He has a big, big challenge to now get in front of Theo [Walcott]. I know that Theo is a very strong-willed guy as well and he won't give in easy. It all bodes well for England anyway.

"Alex can go inside, he can go outside, he's got that injection of pace and I think what he needs now is to be consistent in his play. I am sure that is something he will be working on because he's certainly not a stupid boy. Alex is very friendly with Theo and no doubt he will give him the benefit of his experience as well."

The experience for Oxlade-Chamberlain last night ended on 67 minutes when Rice – presumably working on Wenger's orders – sent on the reinforcements. Despite injuries to nine first-team players, Walcott among them, Wenger rested Robin van Persie and Aaron Ramsey but was moved to bring them on with 20 minutes left to shore up a team that was starting to wobble.

This was an Arsenal side picked with the game against Tottenham Hotspur on Sunday in mind and, quite frankly, who can blame Wenger? History tells him that Van Persie is susceptible to injury and if he is played relentlessly he is more than likely to succumb. Leaving him on the bench for 70 minutes last night was a gamble but it paid off in the end.

How will Arsenal fare at White Hart Lane? On last night's defensive performance, they might struggle. If they attack with the daring they mustered in the first 20 minutes then it will make for a cracking game. There was not the kind of evidence, however, that suggests they have the strength to dig in for a result in such a hostile environment.

In between Arsenal's two goals, Mikel Arteta had to lunge in and clear a shot from Rafik Djebbour off the line after his defence had gone to pieces at a corner. It was a sign of things to come.

It was Oxlade-Chamberlain's run on eight minutes from right to left that caught Alex Song's eye and he took the pass from Song – covering at centre-back last night – into his stride. Running across the face of the box he was fortunate that defender Ivan Marcano made a poor challenge. Oxlade-Chamberlain was past him and then past Olof Mellberg and angled his shot back into the left corner of Franco Costanzo's goal.

The son of the former England international Mark Chamberlain, who was at the Emirates last night, Oxlade-Chamberlain, who had only ever played in League One before this season, said that he hoped to be in the squad for Sunday. "It was a really good experience for me. It was a big step up from last season. The game is a lot quicker but this is where I want to play at the top level and I have a lot of work to do."

Within 12 minutes Arsenal had scored again. This time Santos crossed for Oxlade-Chamberlain and when the ball came back to the Brazilian left-back he drove it in at the near post.

At that point it looked quite promising for the home side but the Greek champions have a good side and in the winger Kevin Mirallas they had the first half's best attacking player. However, it was from a set-piece that they scored, Mellberg working the ball to Ariel Ibagaza who crossed for David Fuster to head in.

The mood at the Emirates is still fragile, despite them winning twice within the space of five days, and the anxiety of their team was quickly passed on to the home support. But having struggled towards the end of the first half they showed more resolution after the break, although they never got that third goal which would have made it comfortable.

The closest either side came to another goal was a shot from the Olympiakos captain Vassilis Torossidis which eluded the dive of Wojciech Szczesny and hit the bar. There was another disappointing performance from Andrei Arshavin, who was put in the shade by Mirallas. He got a later shot off after a Ramsey interception but it all amounted to a poor night's work.

Arshavin was not the only one who did not show enough. Marouane Chamakh was poor and Bacary Sagna off the pace. But four points and second place in Group F will do for now for Arsenal. It could be a lot worse.

Man of the match Szczesny.

Match rating 6/10.

Referee C V Carballo (Sp).

Attendance 59,676.