Arsenal were pathetic, Chelsea almost majestic, with Barcelona not able to put up their usual artistic show against Roma as Wednesday night gave us more thrills and spills in the Champions League

The Gunners had one of those "what is going on" European nights again, while Chelsea put their English Premier League misery behind them with some Champions League joy, with defending champions Barcelona starting their campaign with a draw against Roma.

One of the other pre-tournament favourites – Bayern Munich – picked up a bit of a laboured win over Olympiakos, but it will be Arsenal, and another ridiculously poor display, which will take the Wednesday part of Matchday 1 headlines.

Arsenal made a bright start in Zagreb, with Olivier Giroud forcing a really good save from Eduardo off a header, but the moment Dinamo decided to apply the press on the away team's players, the game changed.

It is amazing how easily Arsenal fold when they are pressed by teams – strange, considering the plethora of technically gifted players in their side – and so it proved again.

A couple of warning shots from distance showed the home side were not going to be pushovers, and then Dinamo found the opener on 24 minutes. El Arbi Hillel Soudani slipped in a pass to Josip Pivaric, who found himself through on goal after Alex Oxlade-Chamberlain completely switched off.

Pivaric's strike was saved by David Ospina, in goal for the first time this season, with Petr Cech given a rest, but the ball ricocheted off Alex Oxlade-Chamberlain, who had by then come back to try and make up for his initial error.

Arsenal were stung by that goal from Dinamo Zagreb, but they continued to struggle to create chances at the other end, and their night was compounded on 40 minutes when Giroud saw red for a second bookable offence. His first yellow was given a little earlier for dissent and Romanian referee Ovidiu Hategan, already angered by those choice words from Giroud, which led to the first yellow, had no hesitation in brandishing a second one for a rather soft foul, it must be said.

In the English Premier League, or indeed any experienced referee from a more from a bigger league, would have given the player a talking-to rather than showing a red card, but this referee, probably, allowed his emotions get the better of him and sent a disbelieving Giroud off. Of course, Giroud only has himself to blame for getting that first yellow card, unnecessarily getting under the referee's skin, but the sending off, as a whole, was pretty harsh.

Dinamo went into halftime with that 1-0 and lead and extra man advantage, but most of the Gooners out there would have hoped the second 45 was time for an Arsenal reply.

Not quite. After a decent start from the away team, the match was done and dusted on 58 minutes as Junior Fernandes headed home at the near post off a corner.

Theo Walcott, who likes to score goals in Croatia, got a late consolation, scoring a typically-Walcott goal by getting in behind the defence, latching onto a pass from Alexis Sanchez, and slotting the ball home, but a consolation is all it was, leaving Arsene Wenger and Arsenal his team to ponder over another pathetic European night.

In the other Group F match, Bayern Munich won 3-0 away to Olympiakos, with Thomas Muller scoring a freak goal off a cross from the right, before Mario Gotze made the points safe in the 89th minute, with that man Muller again netting, this time from the penalty spot, in stoppage time.

At the Stadio Olimpico, Barcelona opened the scoring courtesy one of the MSN trio. A clipped pass from Jeremy Mathieu found Ivan Rakitic in behind the Roma defence, with the Croatian then crossing the ball for Luis Suarez to head home on 21 minutes.

After the opening goal, you felt this match would only go one way – Barcelona's – but Roma fought back ten minutes later, with Alessandro Florenzi netting a sumptuous the equaliser. The midfielder ran down the right wing, before deciding to take a shot from just inside the Barcelona box. The ball flew over Marc Andre Ter Stegen, before banging off the underside of the crossbar and smashing into the net.

At Stamford Bridge, Jose Mourinho was a happy man again, as Chelsea ran-out comfortable winners over Maccabi Tel Aviv, with the Brazilian playmakers Willian and Oscar getting the first half goals, before Diego Costa and Cesc Fabregas added a third and fourth in the second half.

Eden Hazard missed an early penalty, after Willian was fouled by Maccabi Tel Aviv goalkeeper Predrag Rajkovic, but the Brazilian made it 1-0 to the home side on 15 minutes as his freekick evaded everyone and crept into the bottom corner.

Just before halftime, former Chelsea defender Tal Ben Haim conceded another penalty, bringing down Diego Costa, and Oscar stepped up, instead of Hazard, to bury the ball into the back of the net. The icing on the cake was added by Costa in the 58th minute and Fabregas late on.

Results: Group E: Roma 1-1 Barcelona; Bayer Leverkusen 4-1 Astana.

Group F: Dinamo Zagreb 2-1 Arsenal; Olympiakos 0-3 Bayern Munich.

Group G: Chelsea 4-0 Maccabi Tel Aviv; Dynamo Kiev 2-2 FC Porto.

Group H: Valencia 2-3 Zenit St. Petersburg; Gent 1-1 Lyon.