David Moyes branded Manchester United's defending "terrible" and "stupid" following their 2-0 loss to Everton on Sunday.
The Scot suffered a miserable first return to Goodison Park, as a Leighton Baines penalty and Kevin Mirallas' narrow strike handed Everton a comfortable victory.
Baines tucked away the 28th-minute spot-kick after Phil Jones had inexplicably handled Romelu Lukaku's shot, and Moyes was left distinctly unimpressed by his side's defensive showing.
"We gave away two terrible goals," he told Sky Sports.
"We get done by two stupid decisions - well, a stupid decision to dive in front of the ball in one of them.
"Prior to that we had passed the ball well, kept it well, and were in control of the game.
"We played well in the first half, but didn't have a final through-pass or a final finish, that was the disappointing part."
The defeat means it is now mathematically impossible for United to reach the top four and a spot in next season's UEFA Champions League.
Moyes confirmed the blow would be painful to take, but insisted work is going on "behind the scenes" to improve his squad ahead of next season.
"It does (hurt), because it's part of this club and we want to be in it," he said.
"We want to get back in it as quickly as we can.
"We're going to try to get a team that can win better than this team can."
|Coach: Roberto Martínez|
for S. Distin 46'
for R. Barkley 70'
for K. Mirallas 90+4'
|UEFA Champions League Review: Ajax crash out after home defeat|
|Blackpool handed suspended deduction|
|Bayern Munich 3 Milan 0: Guardiola and De Jong lock horns in tunnel|
|Akpom, Ojo and Solanke on the move|
|McClaren: No Newcastle bid for Austin|
|Real Madrid 2 Tottenham 0: Bale on target against former club|
|Mangala vows to improve on debut campaign|
|Tomlin completes Bournemouth switch|
|Astra v West Ham: Page hungry for first-team action|
|Di Maria arrives in Qatar for PSG medical|
|Vitesse v Southampton: Caulker prepared to wait for his chance|
|UEFA rejects Fenerbahce´s Fred appeal|
|Watford show support for assaulted fan as police charge six|
|Ibrahimovic to miss PSG opener|
|Klopp suited to Bayern job - Watzke|
|Eredivisie season-opener postponed due to police strike|
|Dortmund v Wolfsberger: Tuchel set for home bow|
|Griezmann at the double in Atletico win|
|Japan v South Korea: Halilhodzic calls for ´pride´|
|Mourinho enjoying improved relationship with Abramovich|
|Gradel agrees Bournemouth return|
|Inter switch an ´easy decision´ for Miranda|
|Bojan eyes early comeback|
|Vitesse hopeful over Solanke loan deal|
|Pedro will decide his own future - Luis Enrique|
|Iniesta handed Barcelona armband|
|Kukesi punished after Europa League abandonment|
|Leno hints at Leverkusen exit|
|Benitez explains Ronaldo absence|
|Pochettino backs Kane to be among world´s best|
|Messi not ruled out of Mexico friendly - Martino|
|China v North Korea: Kim´s side look for another win|
|River Plate v Tigres UANL: Copa Libertadores final evenly poised|
|Real target Ceballos focused on Betis - Mel|
|Torres: I´d give my life to win La Liga with Atletico|
|Platini can lead FIFA change - Fernandez|
|Mel: Betis won´t be signing Osvaldo|
|Ferrero defends Samp boss Zenga|
|Pochettino expects Spurs improvement|
|Bale ideal for United - Robson|
|Ferdinand: Di Maria will regret United failure|
|Benitez pleased with goalkeepers as De Gea transfer saga continues|
|Guardiola tips fit Schweinsteiger to shine|
|Confident Oxlade-Chamberlain hits back at Keane|
|Ferdinand: Stones would be ´a lunatic´ to join Chelsea|
|Qarabag v Celtic: Gordon wants positivity from Scottish champions|
|Higuain rejects extension from Napoli|
|Zamora returns to Brighton|
|West Ham can cope without Valencia - Gold|
|Wickham loses on Palace debut|
|Guardiola: No problem with Matthaus and Effenberg comments|
|Cartabia excited by Deportivo loan|
|Lyon confirm Rafael deal|
|Hysaj agrees deal to follow Sarri to Napoli|
|Rafael says his goodbyes to Manchester United|
|Dos Santos ready to get going with Galaxy|
|Pochettino rejects Soldado exit talk|
|Metatarsal misery for Mulumbu|
|Benitez: Benzema and Bale going nowhere|
|Mihajlovic: Ibrahimovic would make Milan title contenders|
|Hughes not taking any risks with Bojan|
|Guardiola relishing Audi Cup test|
|Di Maria ´taking a step up´ - Silva|
|Leicester bring in defender Benalouane|
|Deulofeu doubtful for Premier League opener|
|West Ham striker Valencia out for three months|
|UEFA: Qarabag-Celtic to go ahead|
|Palace seal Wickham swoop|
|Ronaldo and Benzema to miss Audi Cup|
|Marotta: Juventus could lose Pogba|
|Kante completes Leicester switch|
|Khedira ruled out for two months|
|FA accepts Mourinho criticism of Wembley surface|
|Robben rubbishes injury talk|
|Marchisio expects Milan title challenge|
|Rafael set for Lyon move|
|Celtic ´seeking reassurances´ over Qarabag pitch|
|Wenger beating Mourinho does not affect Chelsea - Zouma|
|Rooney moved by Everton welcome|
|Mancini not worried by lack of Inter goals|
|Coloccini wants to finish career at Newcastle - McClaren|
|Ramsey: Pressure to win trophies is nothing new|
|Terry: Wembley defeat could be a ´blessing in disguise´|
|Blatter not running for IOC re-election|
|Bendtner: Wolfsburg can challenge Bayern for Bundesliga honours|
|Liverpool relishing Britannia return, says Henderson|
|Everton big enough to keep Stones - Martinez|
|MLS Review: Fire stun Dallas as goals dry up|
|New Atletico signings excite Raul Garcia|
|Cahill expects Arsenal title challenge|
|Jovetic happy with Inter debut|
|Luis Enrique: Barca defence must improve|
|Yanev calls for calm after ugly scenes in friendly|
|Coppa Italia Review: Cittadella romp to victory, Brescia rely on penalties|