Arsène Wenger bore the expression of a man who had just dropped his keys and seen them slip through the hole of a drain cover. His Arsenal team have lost the aura of champions-elect, having drawn their past four matches in the Barclays Premier League, all games that they had been expected to win.

It may sound ludicrous, given that they are level on points with Manchester United at the top of the table, but Arsenal are perilously close to resembling a team who are not concentrating on winning the league. Wenger arguably does not have the resources, comparatively, to succeed in both the Champions League and the Premier League and is being forced to choose between the two.

“There was a little fraction less of belief,” the Arsenal manager said, but it takes only a fraction to upset a team’s momentum so that they fall short in the title race. It all began as a stutter last month away to Birmingham City, a match that his players found emotionally draining and distracting after seeing Eduardo da Silva carried off with an horrific leg injury.

“There is no obvious reason for it [Arsenal’s slump], apart from the fact that we dropped two unbelievable points at Birmingham and that has maybe had consequences on our Premier League form,” Wenger said. “But you have to deal with it and I don’t believe it’s a good enough explanation.”

The explanation, from Middlesbrough’s perspective, was obvious. “If you let them play through you, they are going to kill you,” Jérémie Ali-adière said. “That was the plan, to be tight at the back.”

Aliadière, a player Wenger rated, but not highly enough to keep him at Arsenal, took his goal well, elegantly latching on to Tuncay Sanli’s sprightly cross from the left wing. “It was very special to come back for the first time and get a goal,” Aliadière said. “I was here nine years and you can’t just forget that. It is still my club, even though I didn’t play as much as I wanted to. I always look for their results and I still support them.”

Wenger said that there was “nothing revolutionary” in Middlesbrough’s tactics to force Arsenal wide and limit their ability to play through the channels, but then there was little revolutionary in Arsenal’s efforts to overcome the obstacle. The home team enjoyed much possession, but their finishing was sloppy and the home supporters sounded frustrated even before Aliadière gave Middlesbrough the lead midway through the first half. Robin van Persie needs decent-size chunks of first-team action to regain full fitness after his knee injury and performed well below his standards.

If Arsenal’ s dip in form was prompted by the gruesome sight of Eduardo’s jutting bone, they have to hope that they have experienced a form of closure with the injury to Gaël Clichy. Medical staff hurriedly attended the defender after Mido had inadvertently caught him on the face with his studs, but it was not as bad as it first looked. Gareth Southgate, the Middlesbrough manager, would like Mido’s red card overturned and Wenger would like an end to frustrating, below-par performances.

“There was a big disappointment in the dressing-room,” Wenger said. “It was like a defeat. It is the flattest I have seen them after a game. We need to win the games now. We can do it, but first we want to turn our form around again, lift the spirits and focus on the next one. It will be very interesting on Sunday because we go to Chelsea and Manchester United play Liverpool as well, so we will have a better idea next Sunday night as to what will happen until the end of the season.”

Any neutral watching events unfold on “Grand Slam Sunday” may root for Arsenal, given their style of play, but their equaliser against Middlesbrough was far from beautiful. Kolo Touré met a corner from Cesc Fàbregas that Mark Schwarzer would surely have dealt with had Andrew Taylor not jostled his own goalkeeper. It was the visiting team’s first piece of messy defending and it cost them the chance to record a second successive victory over Wenger’s team.

“I don’t take particular pleasure from taking points off Arsenal,” Southgate said. “I’ve got so much admiration for Arsène and the way they play.

I’m chuffed we’ve done it, but I love the way they play and hope they’re very successful between now and the end of the season. I know on another day they could have beaten us by four or five.”

Southgate was bursting with praise for the manner in which his players restored pride after their poor display against Cardiff City in the FA Cup sixth round the previous weekend. “We were in the depths of despair on Monday, supporters were angry and frustrated and that pain is difficult to repair because you only get one chance in the Cup. But the league games were crucial and we knew everyone else would expect us to take nothing from these two games [against Aston Villa and Arsenal]. We’ve taken two invaluable points, but it’s the manner of the performances which has been important.”

How they rated

Arsenal (4-4-2): M Almunia 6 – B Sagna 6 W Gallas 5 K Touré 7 G Clichy 6 – E Eboué 6 F Fàbregas 7 M Flamini 6 A Hleb 5 – R van Persie 5 E Adebayor 6 Substitutes: T Walcott 6 (for Van Persie, 62min), N Bendtner 5 (for Sagna, 62), P Senderos (for Clichy, 89). Not used: J Lehmann, Gilberto Silva. Next: Chelsea (a).

Middlesbrough (4-4-2): M Schwarzer 6 – L Young 5 R Huth 6 D Wheater Y 7 E Pogatetz 6 – G O’Neil Y 6 M Shawky 6 G Boateng 7 S Downing 7 – Tuncay Sanli 6 J Aliadière 6 Substitutes: L Cattermole 5 (for Shawky, 46), A Taylor 5 (for Tuncay, 68), Mido (for Aliadière, 78). Not used: R Turnbull, J Arca. Next: Derby County (h).