We will buy a powerful centre-half, says Wenger

Arsène Wenger has admitted that he needs to make two top-class signings to his Arsenal squad this summer, with a powerful central defender and a "creative player" his priorities.

Speaking at a question-and-answer session to the club's shareholders yesterday, the Arsenal manager conceded that his team had been undone this season when they faced Manchester United and Chelsea by a lack of strength in defence, especially when faced with "long balls".

Wenger appears finally to have lost faith with Philippe Senderos's prospects of becoming a commanding central defender while, if Arsenal are searching for another central defender, it would also seem to raise question marks over Kolo Touré's place in the team.

At the Q&A session, held at the Emirates Stadium, the Arsenal manager received a more uncomfortable reception than in the past, with questions raised over several members of his squad and also how the team's season had fallen apart in a few short weeks.

It will not help the mood of Arsenal supporters that it has now emerged that Wenger did indeed attempt to sign Jonathan Woodgate from Middlesbrough in the January transfer window – only to find that the England central defender was already in advanced negotiations with Tottenham Hotspur.

There have been strong hints that Arsenal are interested in the 22-year-old Valencia defender Raul Albiol, although the Spain international may cost far more than £10m, the amount which has so far been mooted. Also far in excess of that figure would be a move for Micah Richards, who has become unsettled at Manchester City over the imminent sacking of the manager, Sven Goran Eriksson, and the decision of club captain – and the England international's friend – Richard Dunne to leave this summer. Richards, an Arsenal fan, signed a new contract at City only earlier this year. His unhappiness is also being monitored by Manchester United, although it is unlikely that City will sell.

Wenger, in the Q&A session on Monday evening, lamented the departure of Mathieu Flamini to Milan on a free contract – he will officially sign for the Italian club on 1 July, the day after his contract expires – and said he was "disappointed" with the 24-year-old midfielder's actions. Flamini is being paid €4m (£3.2m) a year, after tax, which is far more than he was offered to stay at Arsenal, because he is a free agent.

Nevertheless, Wenger admitted that Arsenal had not handled negotiations with Flamini very well, especially as he was allowed to run down his contract into its final year – and leave without a transfer fee being paid to the club.

Wenger launched an impassioned plea for his squad to stick together. "We were close this year but we did not win and what I expect from my team is that, if you are a winner, you say, 'Let's come back next year and win'," he said. "If our players are not capable of doing that and just want to walk out for bigger contracts, for me that would be the biggest disappointment."