Arsenal defender Per Mertesacker has challenged his team to use Saturday's crunch clash at Manchester City to prove they can cope with the pressure of the Premier League title race.
Arsene Wenger's side head to Eastlands still reeling from a 2-0 defeat against Napoli on Wednesday which could prove a fatal blow to their hopes of winning the Champions League.
The Gunners needed just a point to finish top of their group and secure an easier draw in the last 16, but instead they slumped to second place and will now face either Barcelona, Bayern Munich, Real Madrid, Paris Saint Germain or Atletico Madrid.
It was a major setback just days after a frustrating 1-1 draw against Everton stopped Arsenal opening up a seven-point lead at the top of the Premier League.
In the circumstances, another defeat against City, who have won all seven of their home league matches and scored 29 goals in the process, would be a disaster heading into the busy Christmas programme.
And Germany centre-back Mertesacker knows the critics are once again starting to question whether Arsenal have the mental strength to overcome the psychological scars of the club's eight-year trophy drought.
"Now everybody is questioning our group and asking if we can maintain that level, so we have to stay together and think that 'yes, we are strong enough'," Mertesacker said.
"It is always difficult, especially after 15 games in the league and with the Christmas period coming.
"You think you have a good chance to achieve something this season, but you have to keep your momentum and that is really important."
While Arsenal hope to cement their position at the top, fourth-placed City can't afford to lose their 100 percent home record if they want to stay in touch with the leaders.
Manuel Pellegrini's team are already six points behind Arsenal thanks to some disappointing results on their travels and England midfielder James Milner concedes this weekend's match will have a major influence on City's hopes of regaining the title they won in 2012.
"With the gap Arsenal have at the top, if they win or we win, things are going to look very different, so it is important we get the victory," Milner said.

FIXTURES
Saturday
(1500GMT unless stated)
Cardiff v West Brom, Chelsea v Crystal Palace, Everton v Fulham, Hull v Stoke (1730GMT), Manchester City v Arsenal (1245GMT), Newcastle v Southampton, West Ham v Sunderland
Sunday
Aston Villa v Manchester United (1330GMT), Norwich v Swansea (1330GMT), Tottenham v Liverpool (1600GMT)