Eden Hazard's majestic solo strike capped a thrilling Chelsea fightback in their 2-1 win at Liverpool, while Tottenham survived a penalty shoot-out to beat Watford in the League Cup third round on Wednesday.
Arsenal advanced to the last 16 with a 3-1 win over Championship side Brentford, while West Ham demolished fourth-tier Macclesfield in an 8-0 rout that ranked as their biggest victory for 35 years.
But it was the drama at Anfield that stole the spotlight as Chelsea became the first team to stop Liverpool winning this season.
Jurgen Klopp's side had won seven consecutive matches in all competitions and the Premier League leaders were on course for number eight when Daniel Sturridge's brilliant effort put them ahead in the second half.
But Emerson Palmieri bagged Chelsea's late equaliser before Belgium star Hazard danced through the Liverpool defence to notch the winner with five minutes left.
It was an impressive comeback from Maurizio Sarri's men, giving them valuable momentum ahead of Saturday's more significant Premier League clash between the teams at Stamford Bridge.
Chelsea are currently in third place, two points behind Liverpool after an unbeaten start to the season.
Both managers made eight changes from last weekend's league matches, with Hazard among the Chelsea substitutes.
Sturridge gave Liverpool the lead in spectacular fashion after 58 minutes.
Liverpool goalie Simon Mignolet denied Chelsea's Alvaro Morata had an early scoring opportunity
Naby Keita's shot was pushed out by Willy Caballero and Sturridge threw himself into an audacious scissor kick that flashed into the net for his third goal of the season.
Chelsea equalised in the 79th minute as Italy defender Emerson tapped in after Simon Mignolet could only parry Ross Barkley's powerful header.
That goal needed VAR to confirm there were no Chelsea players offside, but there was no doubt about the visitors' 85th minute winner.
Taking possession on the right edge of the Liverpool area, Hazard embarked on a superb, twisting run that ended with a blistering shot past Mignolet.
Temporarily homeless Tottenham ignored their unfamiliar surroundings to see off Watford after a 2-2 draw at Stadium MK.
Tottenham's new 62,000-seat arena at White Hart Lane has been delayed by safety issues.
Mauricio Pochettino's side have been playing their home games at Wembley but because the national Stadium was not ready after the Anthony Joshua boxing match on Saturday, they were forced to borrow Milton Keynes Dons' ground.
Dele Alli converted the winning penalty kick to hand Tottenham a dramatic win over Watford
Dele Alli, named Tottenham captain on his return to the venue where he started his career, would finish as Tottenham's key man.
But Tottenham's understudies fell behind when Nigerian forward Isaac Success struck 40 seconds after half-time.
Christian Kabasele's foul on Alli in the 82nd minute led to the Watford substitute's dismissal and a penalty for Tottenham.
England star Alli picked himself up to score the spot-kick before Erik Lamela put Tottenham ahead four minutes later.
Etienne Capoue equalised in the 89th minute, but Tottenham goalkeeper Paulo Gazzaniga saved two penalties in the shoot-out before Alli fittingly scored the decider.
In their first meeting with Brentford since 1947, Danny Welbeck headed Arsenal into the lead after just five minutes at the Emirates Stadium and the forward struck again in the 37th minute.
Alan Judge got one back for Brentford with a deflected free-kick in the 58th minute.
But Alexandre Lacazette's 90th minute goal ensured Unai Emery's side held on for their sixth successive win in all competitions.
At the London Stadium, West Ham gave Macclesfield, who currently sit bottom of the entire Football League, a lesson in ruthless finishing.
Michail Antonio headed the opener in the 29th minute and Robert Snodgrass doubled West Ham's lead three minutes later.
Lucas Perez and Ryan Fredericks were next to score and Angelo Ogbonna netted the fifth.
Snodgrass got his second on the hour and debutant Grady Diangana scored twice in the closing stages.
Nottingham Forest eased through with a 3-2 win over fellow second tier side Stoke at the City Ground.