LONDON - For long spells, Arsenal made European Cup holders AC Milan look ordinary at Emirates Stadium on Wednesday - but failed to take a decisive advantage as the first leg of their Champions League last-16 tie ended goalless.
The Gunners - looking to bounce back from the 4-0 FA Cup thrashing at Manchester United on Saturday - more than matched their Serie A opponents, with World Player of the Year Kaka having only a limited impact.
Manager Arsene Wenger had labelled the encounter the "ultimate test" of his young side, who lead the English Premier League by five points.
However, their performance, while spirited, lacked a real cutting edge in front of goal as Arsenal could not make the most of their dominance, particularly at the start of the second half - with in-form striker Emmanuel Adebayor seeing his stoppage-time header come back off the crossbar.
Nevertheless, the 2006 Champions League finalists remain very much alive heading into the return leg in Italy in a fortnight's time, when the young Gunners will indeed have to produce their performance of the season to advance.
It had been a lively opening to the match, Arsenal's 100th in the Champions League, a century completed under Wenger.
Massimo Ambrosini saw his header saved well by veteran Jens Lehmann - again deputising for Manuel Almunia, who has been struggling with a virus.
Arsenal - unbeaten in 19 home European ties before tonight's encounter - were forced into an early change when Kolo Toure was struck in the back of the thigh by Pato's fierce strike. The Ivory Coast centre-half had to be replaced by Philippe Senderos.
The Gunners, though, did not look to sit back, and mounted a quick counter attack from a long throw by Lehmann, which picked out Adebayor.
The gangly Togo frontman skipped clear of the defence, only to see his path to goal blocked by a saving tackle from Massimo Oddo.
Milan - seven times European champions - remained patient, but Arsenal continued to press.
Both Eduardo and Senderos nearly connected with a Cesc Fabregas corner as the Gunners looked to make the most of their possession inside the opening 20 minutes.
The Spaniard then clipped a lovely ball forwards into the path of Adebayor, who got just far enough ahead of marker Kakha Kaladze, but could not keep his 18-yard effort down.
AC Milan, conversely, offered little in terms of attacking threat, with Brazilian ace Kaka hardly involved at all.
The Italians' frustrations were shown when Pato received a caution for pushing over Bacary Sagna as he chased a hopeful long ball into the Arsenal area.
Arsenal continued to work the ball around well, this time freeing Emmanuel Eboue - sent off in the FA Cup humiliation at Old Trafford - on the overlap down the right.
The Ivory Coast midfielder cut inside before squaring the ball back to Mathieu Flamini on the edge of the box, but his low shot lacked power and was easily gathered by Zeljko Kalac, who had been a major doubt because of a finger injury.
It was then the Frenchman's turn to weave into the penalty area, this time down the left, but his centre was cut out at the near post.
Arsenal maintained the pressure at the start of the second half, forcing a couple of corners, and the Gunners should have been ahead after 53 minutes.
Alexander Hleb skipped clear down the right before cutting inside and teeing up Eboue on the edge of the box.
However, the midfielder scuffed his shot into the ground and the ball bobbled wide of the far post.
Adebayor then did have an effort in the net, but was clearly offside following another fine run and pass from Belarus winger Hleb.
Arsenal were relentless and in full flow now, with Eduardo sweeping an effort just over after another swift counter-attack.
There was a momentary lapse of concentration in the Gunners' rearguard just after the hour, when Senderos inexplicably backed off Oddo, but the defender blasted his angled drive wide.
After such a bright spell, the tempo of the hosts dropped, as Milan started to enjoy some useful possession of their own.
Wenger made a change with 17 minutes left when Nicklas Bendtner replaced Eduardo.
Space suddenly opened up for Fabregas in a central position, but his low 20-yard effort was too close to Kalac.
Eboue was cautioned for diving following a challenge from Alberto Gilardino in the AC Milan area, as the Gunners' frustration at being unable to find a goal started to show.
At the other end, Lehmann held on to a near-post flick from substitute Alberto Gilardino.
Then, deep into stoppage time, Adebayor saw his close-range header come back off the crossbar from Theo Walcott's cross as the tie remained delicately poised heading into the return leg at the San Siro in a fortnight's time.
