By John Cross Mikel Arteta admits Arsenal need a psychological “reset” after being dumped out of the FA Cup by Liverpool. Liverpool are still fighting on four fronts after reaching the fourth round as Arsenal were punished for their wayward finishing and not having a ruthless striker. Arteta admitted it is “not realistic” for Arsenal to have any hope of signing a striker this month even though Gabriel Jesus has also suffered a knee injury and is facing a lay-off. Gunners boss Arteta, whose side now have a winter break after losing their last three games, said: “I think we need to reset. This …