Arsenal boss Arsene Wenger insists the Gunners can still win the title - but admits their thrashing at Liverpool "raises questions" about his side.
The Gunners started the day as Premier League leaders but could have lost by more than the 5-1 scoreline at Anfield.
Wenger's team play Manchester United at Emirates Stadium on Wednesday.
He said: "It raises questions that we have to answer on Wednesday night. I still think we can win the league because mathematically it is possible."
The Frenchman's side were four goals down inside 20 minutes against Liverpool.
Martin Skrtel finished from two set-piece deliveries to give the Reds a cushion after 10 minutes and Arsenal, buoyed by the return of midfielder Jack Wilshere from injury, failed to muster a response.
Raheem Sterling joined Skrtel in scoring twice, while Daniel Sturridge also hit the net for a rampant Liverpool before Mikel Arteta pulled a goal back from the penalty spot.
Watched from the stands by owner Stan Kroenke, the Gunners suffered their first away defeat since the 6-3 drubbing by title rivals Manchester City at Etihad Stadium in December.
And Wenger said his "whole team" failed to perform at Anfield.
"It is always what you make of a defeat that decides your future. We have a lot to answer and a lot of answers to find," he added.
"It is perhaps better I don't talk too much and get on and respond well against Manchester United on Wednesday because I include myself in that performance."
After United's visit to north London, Arsenal face Liverpool in the FA Cup fifth round next weekend, before a Champions League last-16 game against Bayern Munich.
The run of fixtures, with key players such as Aaron Ramsey and Theo Walcott sidelined with injury, has been billed as crucial in Arsenal's season - and Wenger expects more from those available than was on show on Merseyside.
The 64-year-old added: "The performance overall was poor on concentration and pace and our defensive stability was very poor. We always looked vulnerable defensively so it is congratulations to Liverpool. They were the best team and we were very, very poor.
"We conceded two early goals on set-pieces and then you are in a position where you have to come out but we knew we had to be focused and at that kind of level. Our overall performance was just not good enough.
"We are very disappointed but let's not lose our confidence and belief that we can do it."