Leicester City grabbed second-half goals through Shinji Okazaki and record signing Islam Slimani to earn a 2-0 victory over Liverpool in the League Cup third round on Tuesday.
A night of wholesale team changes for the 11 Premier League sides in action produced one notable upset with top flight Stoke City losing 2-0 at second-tier Bristol City.
Former England manager Roy Hodgson enjoyed his first victory in charge of Crystal Palace as the Premier League's bottom club defeated Huddersfield Town 1-0 at Selhurst Park.
Tottenham Hotspur were frustrated for 65 minutes at Wembley by second-tier Barnsley before Dele Alli secured a 1-0 win and a first domestic victory of the season at their temporary home.
West Ham United beat second-tier Bolton Wanderers 3-0 at the London Stadium while Swansea City dispatched Reading 2-0.
Liverpool's Alex Oxlade-Chamberlain was given his first start by manager Juergen Klopp following his move from Arsenal, while Phillipe Coutinho was also in the lineup at the King Power Stadium where the visitors dominated play before the interval.
Coutinho was instrumental in eight-times League cup winners Liverpool's superiority but he went off at halftime with the score still level and after the break Liverpool paid dearly for failing to take their chances.
Klopp's side did not deal with a corner in the 65th minute and Okazaki's deflected shot crept inside the post. Algerian Slimani scored the home side's second goal with a stunning left-foot shot into the top corner in the 78th.
"We led a charmed life in the first half and Liverpool could have been out of sight," Leicester manager Craig Shakespeare said.
"To get the first goal was massively important."
The teams meet again at the weekend in the Premier League.
Bristol City's Famara Diedhiou and Matty Taylor were on target at home to Stoke, while Palace found some respite after losing all five of their league games to edge past top-flight rivals Huddersfield thanks to Bakary Sako's early goal.
Bournemouth enjoyed their second victory over south-coast Premier League rivals Brighton & Hove Albion in five days as Josh King's goal in extra time gave them a 1-0 win.
A clash of two former League Cup winners saw Middlesbrough beat Aston Villa 2-0 away, while Norwich City, who have also won the competition, beat fellow second-tier side Brentford 2-0.
Bristol Rovers, one of two third-tier clubs in round three, went down 1-0 to Wolverhampton Wanderers after extra time.