Two first-half goals from Red Star Belgrade striker Milan Pavkov consigned last year's beaten finalists, Liverpool, to a shock Champions League defeat in the Serbian capital.
Liverpool thumped Red Star 4-0 in the reverse fixture at Anfield two weeks ago but the tables were turned early on in Belgrade as the home side took control.
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A deflected Andy Robertson cross struck the Red Star crossbar in the second period while Mohamed Salah struck the post with a shot from the edge of the box.
But Red Star were worthy of the victory -- the first they have claimed in the Champions League for 26 years -- in front of a noisy and passionate home crowd in the Rajko Mitic Stadium.
Liverpool midfielder James Milner told UK broadcaster BT Sport that Liverpool had problems "all over the field" in the first half and never properly recovered.
That was of little concern to Red Star's players, however, as they joined arms and took the acclaim of their supporters on the full-time whistle.
The result leaves all very much to play for in terms of qualification from Group C, which also features Napoli and Paris Saint Germain.
The French and Italian sides also played out an entertaining 1-1 draw, with Juan Bernat scoring just before halftime to put the French Ligue 1 leaders ahead, before Napoli's Lorenzo Insigne equalized from the spot, when Jose Callejon was felled by PSG goalkeeper, Gianluigi Buffon.
No Shaqiri or Firmino
Liverpool started the game at the top of Group C and knew victory would move them to the brink of qualification for the last 16.
But the Anfield club were without attacking midfielder, Xherdan Shaqiri, who was left at home on Merseyside.
Shaqiri caused controversy at the 2018 World Cup by making a double headed eagle gesture, meant to imitate the Albanian flag, when scoring against Serbia for his adopted nation, Switzerland.
The attacking midfielder was born in Kosovo and is of ethnic Albanian descent. Kosovo declared independence from Serbia 10 years after the bloody conflict between Serb forces and Kosovar-Albanian rebels. Serbia does not recognize Kosovo as an independent country.
Liverpool also chose to start with first-choice striker Roberto Firmino on the bench. In his stead, Daniel Sturridge fitted into Liverpool's attacking triumvirate alongside Mohamed Salah and Sadio Mane.
But It was Red Star marksmen Pavkov who would catch the eye in the Rajko Mitic Stadium.
Pavkov leapt above defenders Virgil Van Dijk and Joel Matip to power Marko Marin's delivery low beyond Alisson in the Liverpool goal with just 22-minutes on the clock.
With the confidence flowing, Pavkov then doubled Red Star's advantage six minutes later, holding off the challenge of Georginio Wijnaldum before steadying himself and firing home from 25-yards out.
Liverpool tried to force their way back into the game and came close through Robertson and Salah. The Egyptian was also denied late on by Red Star goalkeeper Milan Borjan.
But the Serbian champions defended stoically and saw out their historic win in relative comfort.
Elsewhere Barcelona became the first team to make it through to the knockout stages with its 1-1 draw with Inter Milan at the San Siro.
The dropped point by the Italian side, coupled with a late win in London for Spurs, means that there is still all to play for when the two sides meet in the English capital later in November.
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