Upset Alert!In case you missed it, defending FA Cup Champions Arsenal crashed out of the 2017-18 FA Cup after being humbled by Nottingham Forest 4-2 in the third round last night.As things usually are during a result that raises eyebrows, this one was also marred by a controversial decision - a late penalty to Nottingham Forest and a slip-up while taking it, which was eventually declared as a goal. Debates will go on about those incidents, but it was nowhere near a performance that is expected from a club of Arsenal's stature.There have been countless calls of #WengerOut over the years, and this game ended up adding more fuel to that fire. People took to Twitter to voice their opinions, and here are some of the best tweets to come out of that:What a joke of a club @Arsenal losing 4-2 to Nottingham Forest ?Retweet if your laughing at Arsenal! ??#NFFCvAFC pic.twitter.com/4FbpUHYi2Z— Pogba_Lukaku (@Pogba6_Lukaku9) January 7, 2018Arsenal's grip on the #FACup. #AFC#NFFCvAFC pic.twitter.com/f4EWaPc9zZ— Gazza ? (@up_the_clarets) January 7, 2018#AlexisSanchez on his phone to his agent be like....#AFC #FACup #NFFCvAFC pic.twitter.com/Bv2g7fNfSZ— Phil Muspratt (@philswim85) January 7, 2018Arsenal fans singing "Arsene Wenger, he's won more than you" at #NFFC fans. Awkward. Considering Forest have won two European Cups. #NFFCvAFC— Imran Esc?bar (@razor5edge) January 7, 2018Forest fans walking into work on Monday like...what a result! ?? #NFFCvAFC pic.twitter.com/wgBam7foIR— Jermaine Jenas (@jjenas8) January 7, 2018Currently 6th in the prem, playing Europa league football, crashing out of the FA Cup to a pub side, Alexis and Özil haven’t renewed their contracts with less than six months to go and 23 points behind City.. #OhToBeAGooner #NFFCvAFC #WengerOut #EnoughIsEnough #Arsenal— Kristoffer Grønning (@kgroenning) January 7, 2018Managerless Nottingham Forest have done what no team have done in 21 years - beaten Arsene Wenger’s Arsenal in the 3rd round of this wonderful competition ??????The game that had it all! #NFFCvAFC— Jules Breach (@julesbreach) January 7, 2018?- Cost of Forest’s starting 11: £5.2M- Cost of Danny Welbeck: £20M#NFFCvAFC #NFFC pic.twitter.com/0OwcFieTiE— The Sportsman (@TheSportsman) January 7, 2018? The last time Arsenal went out in the FA Cup 3rd round was 1996Ben Brereton wasn't even alive#NFFCvAFC#NFFC pic.twitter.com/yikJTh19qa— The Sportsman (@TheSportsman) January 7, 2018#NFFCvAFC Ozil and Sanchez right now. #Wengerout pic.twitter.com/rMbz92ryjs— Barry Beck (@TheGreat_Barry) January 7, 2018Arsenal really need to step up their game in the upcoming Carabao Cup semi-final clash against Chelsea. If they don't fight for their lives, it's safe to say that the banners will soon be brought out yet again.