Mikel Arteta knows Arsenal must let cooler heads prevail against Liverpool if they are to secure all three points at Anfield on Sunday.The Gunners head into the weekend eight points clear at the top of the Premier League but have a woeful recent history when visiting the red half of Merseyside."We've played in the toughest places," Arteta said."We went to White Hart Lane and did what the team did, and the atmosphere doesn't get much harder than that."