Arsenal may have lost to a Borussia Dortmund team operating for most of this match at a cagey three-quarter throttle, but there will be consolations for Arsène Wenger at the start of a momentum-defining five weeks. Firstly, Arsenal played with a gathering sense of drive for the middle hour of this match, pushing last season's losing finalists back for long periods. And secondly this was a varied Arsenal display, their inspiration towards the end of a difficult first half coming not from that fluid central core, but from Plan B (yes: there is one) in the shape of an excellent, driving performance from Olivier Giroud.

In fact a match that had been billed as a meeting of two outstanding midfields ended up providing something more mixed, marked out in the main by contrasting centre-forward displays from Giroud and Robert Lewandowski. The latter was subdued where Giroud was at times forceful, but provided an expert finish for the winning goal in a 2-1 victory.

Before this match there had been some slightly fevered suggestions that Arsenal, blessed now with a revolving carousel of soft-shoed creators, might have the best midfield in Europe. Time will tell if they even have the best midfield in North London, but the question here was whether they could reasonably claim to have the best midfield in Champions League Group H.

Dortmund remain one of Europe's aristocrats, and a team perfectly geared to testing Arsenal's new-found strength in central areas. For long periods this was a tightly packed and airless experience for Arsenal's cavaliers. At times in the first half Dortmund even performed the neat trick perfected by Bayern Munich of appearing to have more than the regulation 10 outfield players, swarming selectively but with great cohesion in their high-viz yellow shirts.

This Arsenal team, though, has something beyond its midfield riches. This season they have a compelling centre forward in Giroud 2.0: now leaner, more coherent in his linking play, and with energy levels that appear to have been thoroughly Wenger-ised in the past year. Here Giroud was exceptional in the first half and in an exceptional way, too. It is easier for a centre forward to excel when his team-mates are pouring forward behind him. But Giroud did something different here, leading Arsenal back into this match when they might have been shut out of it by Dortmund's yellow-hued midfield suffocation. It was a brave performance as well as a skilful and mobile one, and it came against high-grade opponents.

In fact Giroud had the better of the comparison with Lewandowski, leading his team from the front in what is, let's face it, a most un-Arsenal like manner. Centre forwards have been unfashionable in recent years. But here was a physically commanding non-false No9 taking his hatchet to one of Europe's most stately back-lines.

Before kick-off Dortmund's supporters were, as ever, a brilliant spectacle of concentrated yellow in the Emirates' designated singing section (otherwise known as the away end). It is often overlooked in the ewok-ish underdog version of Klopp's anti-Bayern cavaliers, but Dortmund are a huge club in their own right, with a sense of well-seasoned pedigree on these European nights.

Mesut Özil may have raised both Arsenal's technical levels and their expectations, but this was a concerted step up. Plus, in Sven Bender, Dortmund have perhaps the most effective midfield space-destroyer in Europe, a wonderfully loose-limbed athlete well-equipped to intrude on the spaces in which Özil thrives. Here he began the game by taking the ball away from Özil in a deep central area with a nudge of the hip as a pair of five-men midfields at times threatened to smother one another.

Dortmund have a waspish forger of their own in Marco Reus, another from the endlessly fecund production line of creative German midfielders, and a player with startlingly swift lateral movements, which he used to create the opening goal. Robbed by Ramsey on the edge of the Arsenal box, Reus sprang sideways to win the ball straight back and nudge it to Lewandowski, who passed for Henrikh Mkhitaryan to ease a wrong-footing finish past Wojciech Szczesny.

Giroud led the Arsenal fight-back. First he might have won a penalty, strong-arming past Marcel Schmelzer and then luring Mats Hummels into a trip just outside the box. Then it was Giroud's full-throttle persistence that led to Tomas Rosicky finding space for a shot that Hummels cleared off the line. And on 42 minutes Giroud scored Arsenal's equaliser, seizing on some calamitous hesitation between Hummels and Roman Weidenfeller to smash-volley the loose ball into an empty net. It was terrible defending, but induced in part by Giroud's elegant buffeting.

Arsenal had the better of territory and possession for a while in the second half as Özil switched to the right and began to find space away from the Bender-Sahin lockdown in the centre. It was from Özil's low cut-back that Santi Cazorla trimmed the bar with a fierce shot as Arsenal found their Premier League rhythm in the final 20 minutes. Dortmund have another gear too: they broke with brilliant effect as this Flamini-less Arsenal became a little cavalier for the first time, Lewandowski providing the finish to a high-speed foray down the right.