Bacary Sagna believes Arsenal's players must ask themselves some big questions as they look to beat rivals Tottenham next weekend.

The Gunners crashed out of the FA Cup at Sunderland on Saturday, a result which came on the back of an abysmal performance away to AC Milan, where a 4-0 defeat all but ended their Champions League ambitions.

Manager Arsene Wenger has seen his position come under severe scrutiny this season following an appalling start which left them out of the title race before the turn of the year and now in a real scrap to secure a top-four finish.

Full-back Sagna, however, insists the squad have the quality to produce the required performance next Sunday against their neighbours, who by contrast are enjoying another memorable campaign under Harry Redknapp.

"We have to keep our heads up, work hard and think about the Premier League because we have a derby next weekend against Tottenham," Sagna told Arsenal Player.

"We need to do it for us and for the fans as well. We have to react. We can't play like this against Tottenham otherwise we will lose.

"We have one week to get ready for the game, to question ourselves, to work and to talk to each other.

"We are professional and we have to fight until the end.

"We have to look forwards. We are fourth in the Premier League and we can't let it go like this"

Wenger, 62, has transformed the north London club since his arrival in September 1996, since when they have always been in the top four and qualified for the Champions League in 14 successive seasons.

However, failure to deliver any silverware to Emirates Stadium, the last coming in the 2005 FA Cup final, has led some to question whether the experienced French coach remains the right man to take the club forwards.

Former Gunners midfielder Emmanuel Petit - who won the 1998 Double under Wenger - is in no doubt his former boss can turn things around and laid the blame firmly at the door of the "mentally weak" squad.

"Arsene is still the solution. The players have to look in the mirror, be honest and ask questions of themselves," Petit told BBC Sport.

"They are playing like they don't know what's going on, they don't know what to do on the pitch. Mentally, they are very weak."

Petit added: "They have to bring in more experience and big characters. They need leaders, but you cannot sign big players if you are not in the Champions League.

"Every year they are selling their best players. Arsenal are not a football academy - they're one of the biggest clubs in Europe and need to get back to that level.

"They have to spend money to get the big names, and they must also ask some players to leave."

George Graham guided Arsenal to the old First Division championship twice in 1989 and again in 1991, as well as the 1993 FA Cup.

The Scot, who also had a successful spell as a player with the Gunners in the 1970s, winning the Double, believes Wenger must have a summer clear out.

"I think he will be there next season but he badly needs to refresh the playing side," Graham said.

"They've got money to spend and I can't understand why Arsene did not go out and buy some real quality players last summer."