Manchester - Manchester City's defence of the League Cup was ended by a 2-0 home loss to Newcastle in the last 16 on Wednesday, with an injury to playmaker David Silva completing a miserable night for the out-of-form English champions.
Tottenham and Southampton also won to reach the quarterfinals, where Chelsea and Liverpool — the biggest teams left in the competition — face away matches at second-tier opponents Derby and Bournemouth, respectively.
Young striker Rolando Aarons scored in the sixth minute and France midfielder Moussa Sissoko dribbled through City's defense to add a brilliant second goal in the 76th for under-strength Newcastle, whose season began dreadfully but has been turned around with three straight wins.
Silva, one of City's most important players, came off at Etihad Stadium in the eighth minute after twisting his left knee — four days before the derby against Manchester United in the Premier League.
In the past week, City has lost 2-1 at West Ham to drop six points behind Chelsea in the Premier League and squandered a two-goal lead to draw at CSKA Moscow in the Champions League, where it is struggling to qualify from its group.
"We all wanted to continue in this cup but we couldn't do it because we are not in a good moment," City manager Manuel Pellegrini said.
"We are conceding goals. We are not moving the ball as fast as we normally do. It was not a good week."
Newcastle's reward in the last eight was a trip to Tottenham, which beat second-tier Brighton 2-0 thanks to second-half goals by substitute Erik Lamela and Harry Kane at White Hart Lane.
Southampton won 3-2 at Stoke, with Italy striker Graziano Pelle scoring the winner — his second of the game — in the 88th minute, moments after Peter Crouch was sent off for the hosts at Britannia Stadium.
The victory continued Southampton's superb start to the season, with the south-coast club second in the Premier League behind Chelsea and having won nine of its last 10 games in all competitions.
Southampton, one of five Premier League teams in the draw for quarterfinals, will next play third-tier Sheffield United — the lowest-ranked team remaining.
To cap a stunning night for Newcastle, whose last domestic title was the FA Cup in 1955, midfielder Ryan Taylor completed 90 minutes in his first game for 26 months after two knee ligament injuries.
"I think one of our staff will have to scrape him off his bed tomorrow because he won't be able to move," said Newcastle manager Alan Pardew, whose job was under severe pressure a month ago but now looks more secure.
"It has been difficult the first part of this season but we believe in ourselves (and) have come through that spell."
The 18-year-old Aarons was one of a number of fringe players given a start, with Pardew having one eye on Saturday's early kickoff against Liverpool, but he took his chance to impress by latching onto a loose ball after Fernandinho was dispossessed. Aarons glided past Eliaquim Mangala and shot through the goalkeeper's legs for Newcastle's first goal against City in 525 minutes.
City was sloppy in possession and outfought by Newcastle, with Sissoko clinching victory by powering past Fernandinho and Bacary Sagna before poking his finish into the corner.