Arsene Wenger saluted the leadership of William Gallas after Arsenal reclaimed their position at the summit of the Premier League with a 1-0 defeat of Chelsea at the Emirates stadium. Captain Gallas headed the game's only goal on the stroke of half-time, exploiting a rare clanger by Chelsea goalkeeper Petr Cech, in a match which saw England skipper John Terry limp off in the first half with an ankle injury. Terry will have scans tomorrow and, with Ricardo Carvalho still unfit, a lengthy lay-off could spell problems for Avram Grant's side. Wenger, however, was delighted to see his side bounce back from defeat at Middlesbrough and show steel to go with their undoubted style in a match which contained nine bookings. He was just as pleased to see former Chelsea defender Gallas, who scored the equalising goal in the dying seconds against Manchester United earlier this season, provide the finishing touch after Cech had flapped and missed at a Cesc Fabregas corner. Wenger said: 'He pops up when you need it. He is a leader and that is the best definition of a leader. When you need it he shows the example. He did that against Manchester United in the last seconds. It shows he is a winner. 'I'm not sure I would have jumped behind Cech because I think I would have thought he would have taken the ball. 'Arsenal is a special club. William this season has taken that on board and he is completely the leader and represents how we want to behave. 'He is transformed completely, does a lot of things with the team but also off the pitch which are great for the club.' The victory keeps Arsenal one point ahead of United, six ahead of Chelsea and 10 in front of Liverpool who languish in fifth place. Wenger, however, wants all of England's big four to stay in contention. He said: 'Liverpool have had the biggest disappointment but they are not out of it. Neither are Chelsea because they showed today they are a good team. 'We are confident. The belief is there but I prefer that it remains a four horse race because it is more interesting. It makes a day like today great for the Premier League. As long as there are four teams in it the interest in the Premier League is even bigger. 'We have shown great character in the fight today, in the one-to-one duels. We were dominant on that front and that is not the case usually.' Chelsea boss Avram Grant, whose side tasted defeat for the first time in 17 matches, said: 'Petr Cech is a great goalkeeper with a great attitude but it happens even to the big ones. I'm disappointed it happened in this game. 'It is disappointing but if we continue like this it is not the end of the world. Six points at this time of the season is nothing. It will not be easy, but it is not something that we could not do something about.' Grant believed referee Alan Wiley was correct to show nine yellow cards and did not complain over the treatment handed out to Ashley Cole, who was booed at every turn on his first return to Arsenal since his controversial transfer to Stamford Bridge. Cole was reported to have made a gesture to the Arsenal fans as he left the pitch following an altercation with Cesc Fabregas and Grant said: 'They made a lot of fouls on him, but he is a big boy and it is not a problem. He played well today, it gave him more motivation.' Grant also admitted he was looking at bringing in reinforcements in the January transfer window but admitted: 'If we didn't have injuries and the African Nations Cup, the squad is good enough. 'We are checking everything. We want to bring in players that are good for the quality of the team but it is not easy.' Grant may be handed a boost tomorrow, however, when long-term absentee Michael Ballack has a fitness test and he could even be considered for Wednesday's Carling Cup tie against Liverpool.