Both Crystal Palace and Arsenal have been struggling lately, but nobody watching events unfold on Monday night would have dreamt that the hosts would run out 3-0 victors.The Gunners, who hadn't lost four games in a row under Arsene Wenger – so, essentially, in 21 years – and went into the game looking to get their faltering top four hopes back on track.However, they met a Palace side willing to put in a resolute 'Allardyce performance' and the Eagles put them to the sword to ease their relegation fears.Andros Townsend put Palace ahead early in the first half, and France international midfielder Yohann Cabaye added a second with a brilliant cross-cum-shot in the second period.But if that wasn't bad enough, Arsenal's fate was sealed when third choice goalkeeper Emiliano Martinez was adjudged to have brought down Townsend to give away a penalty.It's hard not to feel for the goalkeeper, who was hardly at fault for Palace's first two goals, as he wasn't given much help from his outfield teammates.On first glance, it certainly looked like a penalty. The Argentine came rushing out and not only did he catch Townsend, but he also appeared to clean out Gunners full-back Hector Bellerin in the process.See for yourself below, you certainly can't blame the referee for calling it as he saw it...But when the video is slowed down, it would seem that Townsend knew the keeper was coming and left a trailing leg for the 24-year-old to catch.Surely incidents like this only serve to strengthen the argument in favour of video replays, though, having said that, we've seen penalties given for much, much less over the years.One thing was for certain, though, and that was the anger of Arsenal fans, who just couldn't believe what they were being subjected to by their team.Check their reactions below...