Arsenal slipped to a disappointing 2-1 Champions League defeat as Olivier Giroud saw red and Dinamo Zagreb recorded their first win in the group stages of the competition for nearly 16 years.
Not since a 3-0 victory over Sturm Graz in September 1999 had the Croatian outfit tasted success at this stage, but Junior Fernandes grabbed the decisive goal to see off the threat of Arsene Wenger's side in Group F.
The visitors were left to rue a host of spurned chances in the first half in Zagreb, before Josip Pivaric's shot hit Alex Oxlade-Chamberlain on its way past David Ospina to open the scoring.
Giroud, who had been particularly wasteful in front of goal, was then sent off by referee Ovidiu Hategan for a second bookable offence just before the break, adding to Arsenal's woes.
More Dinamo pressure eventually brought a second goal as Fernandes sent a bullet header past Ospina just before the hour.
Arsenal's attempts to find a way back into the clash brought a consolation from Theo Walcott, but Dinamo clung on to extend their unbeaten run in all competitions to 42 matches.
The visitors dominated the opening stages and Giroud – one of six Arsenal changes from Saturday's Premier League win over Stoke City – was gifted a glorious chance after nine minutes, but saw his flicked header superbly saved by Eduardo.
Opportunities continued to come for Arsenal and Giroud was again wasteful after 18 minutes, the France international heading against the post before somehow failing to convert the rebound from close range.
And he was made to rue those misses as Dinamo took the lead midway through the half.
A counter-attack from the hosts saw El Arabi Soudani release Pivaric behind the Arsenal defence and, while his effort was saved by Ospina, the loose ball ricocheted into the net off Oxlade-Chamberlain.
Giroud's miserable half ended with his dismissal five minutes before the interval as he swung a leg at Ivo Pinto, the striker catching his man and earning a second booking having earlier seeing yellow for dissent following a clumsy challenge on Domagoj Antolic.
Wenger's side could have been in further trouble soon after the restart as Soudani was given acres of space in the six-yard box, only to see his header thud into Ospina's right-hand post.
Mesut Ozil had an equaliser disallowed for offside in the 54th minute and soon after Dinamo doubled their advantage, Fernandes rising at the near post to head home Paulo Machado's corner.
A late surge from Arsenal saw Alexis Sanchez and substitute Walcott go close and the latter was able to pull a goal back with a composed finish 12 minutes from time.
However, even five minutes of stoppage time was not enough for the visitors and they were grateful to Ospina for a late save to stop Leonardo Sigali extending Dinamo's winning margin.
