London, Feb 4 (DPA) Arsenal travel to Chelsea Sunday knowing that defeat would almost certainly end their hopes of winning the Premier League this season.

After last week's 3-1 home loss to Manchester United, Arsenal's hope seemed thin, but the door opened a fraction on Tuesday as the league leaders Chelsea could only draw at Hull City.

When Arsenal lost 3-0 at home to Chelsea in November, they slipped 11 points behind Chelsea. Now, as goalkeeper Manuel Almunia points out, to have closed the gap to six points represents progress.

'We are on schedule to do good things this season, we have only a little step to get back to the top of the league,' he said.

'When you think about where we were after the Chelsea game, that is a great achievement. Sometimes it is better to come back from third or fourth to challenge than to be at the top all the time.'

Chelsea manager Carlo Ancelotti, after seeing his side again fail to take a opportunity to open up a clear gap over their challengers, admitted he was trouble by their vulnerability to set-pieces.

'We know about it. I know very well how many goals we have (conceded) from set pieces,' he said.

'Every team here in England has a very good jumper and a very good striker and it can happen that you concede a goal. How we score, sometimes we can concede.'

United, who lie two points behind Chelsea, are home to bottom side Portsmouth.

Their faltering season has bee kept o track by the form of forward Wayne Rooney.

'He is 24 now but he is only going to get better,' said midfielder Ryan Giggs in praise of the England striker Rooney. 'His appetite is strong and he is a great player to have in your team.'

Fourth-placed Tottenham face a crucial game in the battle for Champions League qualification as they host Aston Villa, who are two points behind with a game in hand.

Liverpool, a point further back, should welcome back defender Fabio Aurelio from a calf injury for the visit of Everton in the Merseyside derby.

Manchester City, who are level with Liverpool, but have two games in hand, travel to Hull. Midfielder Patrick Vieira, who joined from Inter Milan in January, could make his debut for City after recovering from an ankle injury.

'It has been a frustrating spell with the injury. Thank God it is over and I am ready to start,' he told the club website.

'I suffered it in the last game for Inter and did not realise it was that bad. City have been right behind me and I have to thank them for that.

'I am looking forward to playing in the Premier League again and getting a run of games.'

The key game at the bottom sees West Ham United travel to Burnley, who are yet to win under Brian Laws.