Both Manchester City and Arsenal are in a bit of a hole right now.
They're chasing two-goal deficits and facing daunting away trips to both the Camp Nou and the Allianz Arena respectively, but all is not lost—here are 15 of the greatest European comebacks recorded in the continental competitions.
Martin Demichelis or not, there is always hope when it comes to football.
Last season, Barcelona overcame a two-goal deficit against Milan in the round of 16 in historic circumstances.
They'd been poor at San Siro in the first leg and were bottled up, but after reinstating David Villa as a No. 9 up front, scored four in front of the Nou Camp to sail into the quarterfinals.
It may not seem much, but no team had ever overcome a two-goal swing without an away goal before.
Middlesbrough produced an epic comeback at the Riverside Stadium in 2006 when they overcame FC Basel in a UEFA Cup quarterfinal.
Eduardo scored a tap-in at the back post to make it 1-0 on the night and leave the Teessiders needing four, but Mark Viduka, Jimmy-Floyd Hasselbaink and Massimo Maccarone were equal to the challenge.
Clearly satisfied with doing things the hard way, Middlesbrough found themselves in a hole against Steaua Bucharest in the very next round of the 2006 UEFA Cup (semifinals).
The Teessiders were 3-0 down on aggregate after just 25 minutes of the second leg, but somehow mounted another crazy comeback to win it in the 88th minute—via a Massimo Maccarone header.
In the 1973 European Cup second round, the mighty Ajax fell to a crushing loss to the inconsistent CSKA Sofia.
The Bulgarian outfit had dominated their domestic league but failed on the European stage, and it seemed like nothing would change as Jan Mulder gifted the Dutch outfit a 1-0 lead in the first leg.
However, Dimitar Marashliev leveled matters in Bulgaria, before Stefan Mikhailov struck in extra time to confirm the win. It ended Ajax's reign at the very, very top.
Chelsea traveled to Napoli in the first leg of the 2012 UEFA Champions League round of 16 and lost 3-1.
Before the second leg rolled round at Stamford Bridge, manager Andre Villas-Boas was fired. Roberto Di Matteo replaced him, steadied the ship and helped the Blues stage a four-goal comeback to win 5-4 overall.
It was the same year they won their first-ever European title.
Espanyol had the 1988 UEFA Cup locked up after a 3-0 home win in the first leg...or so they thought.
Despite not scoring the first goal until the 57th minute, Bayer Leverkusen staged a comeback to draw level and force penalties in the second leg at the Bay Arena.
The Werkself were then victrious in the shootout.
Borussia Monchengladbach recorded a 5-1 win over European giants Real Madrid in the first leg of the 1985 UEFA Cup third round, sending the fans into delirium.
Back at the Bernabeu, though, the party was spoiled. Los Blancos scored four, drawing level and emerging victious on away goals.
Real Madrid went on to win the competition.
In 1999, Manchester United faced off with Bayern Munich in the UEFA Champions League final. However, before they earned the privilege to do so, they had to overturn a sizable deficit against Juventus in the semifinal first.
The Bianconeri had grabbed an away goal at Old Trafford to take a 1-1 scoreline back to Turin, and went 2-0 up at home within 11 minutes as Filippo Inzaghi struck twice.
Roy Keane then sparked an incredible three-goal turnaround to lead the Red Devils to the showpiece event.
Once upon a time, it was Queens Park Rangers who were battling Europe's elite in the finest of competitions, but they slipped up pretty badly here.
Taking a 6-2 home win to Partizan Belgrade, most fans thought the tie was a do-over
The Serbian outfit had other ideas, though, and crushed the Hoops 4-0 on their own turf to emerge victorious on away goals.
In 2004, Deportivo La Coruna met Milan in the UEFA Champions League quarterfinals and lost 4-1 at San Siro.
With the likes of Paolo Maldini bolstering the heart of the Rossoneri defence, the Spaniards appeared doomed, but an astonishing 4-0 win back at the Estadio Riazor sealed passage to the semifinals.
Walter Pandiani set the tone for pandemonium in the stands that night.
There is no footage available of this comeback. Pictured is Leixoes playing vs. FC Porto.
A little-known gem for you here.
In the 1962 UEFA Cup Winners' Cup first round (talk about obscure), Leixoes fell to a 6-2 defeat at FC La Chaux-de-Fonds to seemingly end the Portuguese side's chances of success.
However, welcoming the Swiss outfit back for a remarkable second leg, the home side won 5-0 on the night and therefore 7-6 on aggregate.
In 1984, Metz shocked the world by staging an insurmountable comeback against Barcelona in the European Cup Winners' Cup.
The French side lost the home leg 4-2. It was so convincing that the nation's TV stations didn't even bother to televise the match. The Barca players were also extremely condescending, per The Guardian, and it fueled a remarkable stage of events.
Despite going behind in the return leg, Metz went on to win 6-5 on aggregate and lift the trophy.
In 1986, the stage was set for Dynamo Dresden to make a real splash on the European scene.
They drew Bayer Uerdingen in the European Cup quarterfinals and beat them comfortably 2-0 in the first leg, then raced into a 3-1 lead away from home in the second.
Surely that's safe, right?
Wolfgang Funkel converted a penalty to start off an unbelievable comeback, with Bayer finishing up as 7-5 winners overall.
Milan entered the 2005 UEFA Champions League final as favourites and raced into a 3-0 lead by half-time.
Paolo Maldini converted in the first minute from a set piece, then Hernan Crespo added a deluxe double to essentially seal the result at the break.
Liverpool wouldn't lie down, though.
Steven Gerrard led a resurgent second period in which the Reds scored three goals and took the game to penalties.
There, Jerzy Dudek was the hero.
It ranks as our No. 1 ahead of Liverpool's heroics in Istanbul for one simple reason: Manchester United won the game in normal time rather than forcing a draw.
Such slender margins, true, but they were both fantastic in their own way.
Ole Gunnar Solskjaer and Teddy Sheringham will forever be revered for tucking away their last-gasp goals to stun Bayern Munich on Iberian shores.
The German giants had led 1-0 since the sixth minute and looked locks to lift the cup, but football is a cruel, cruel mistress.