Son Heung-min returned to form in emphatic fashion as his double helped Tottenham to a 3-1 victory at West Ham to send Mauricio Pochettino's side into the EFL Cup quarterfinals.
Having opened the scoring with his first goal of the season 16 minutes in, Son, one of 10 changes and making his 150th Spurs appearance, doubled his tally with a composed finish early in the second half to set Tottenham on its way to a second victory at London Stadium in the space of 12 days.
Son's goals – his first since March – were Tottenham's only opportunities of note amid a barrage of West Ham attacks, though, and the host's pressure paid off when Lucas Perez headed in with 19 minutes remaining.
However, West Ham's hopes of a comeback were dashed inside four minutes, Fernando Llorente tucking home from close range to secure progress into the last eight.
Son wasted little time in opening his account for the campaign, picking out the top corner after latching onto a loose ball on the edge of the area.
West Ham rallied quickly and Tottenham had Paulo Gazzaniga to thank when he pulled off a smart stop low to his right to deny Javier Hernandez an equaliser on the stroke of half-time.
Michail Antonio looked set to restore parity shortly after the restart, but the forward failed to beat Gazzaniga after outmuscling Juan Foyth.
Manuel Pellegrini's side were soon punished for its wastefulness, Son pouncing on Arthur Masuaku's error before coolly rounding Adrian.
Perez's header threatened to make things interesting late on, but West Ham's defence was exposed again when Llorente reacted quickest to Christian Eriksen's corner to wrap up the victory.
What does it mean? Pochettino's back-ups come good
With just 48 hours between this game and its defeat to Premier League title rival Manchester City, Pochettino had little choice but to make wholesale changes.
Fortunately for Tottenham, its strength in depth shone through as West Ham, which trounced Macclesfield Town 8-0 in the third round, failed to make its chances count.
Son off the mark in style
Son scored 14 goals in all competitions last term, but following his exploits at the World Cup and then the Asian Games, it has taken time for the South Korea forward to click into gear.
With neither Lucas Moura or Erik Lamela presenting as obvious goalscorers, Son will be hopeful his double has forced him back into starting contention.
Hernandez fails to take his chance
Having made just two Premier League starts this season, Hernandez needed to grasp his opportunity with both hands on Wednesday if he is to mount a challenge to Marko Arnautovic, but despite finding himself in good positions, the former Manchester United striker failed to take advantage.
Key Opta Facts
- Tottenham has reached the League Cup quarterfinal for the first time since 2014-15, when it eventually lost in the final to Chelsea.
- West Ham has lost consecutive competitive matches against Spurs for the first time since February 2013.
- The Hammers' Lucas Perez has been directly involved in five goals in his six games in the League Cup (four goals, one assist).
- Son Heung-Min scored his first goals for Spurs since March, ending a run of 19 games in all competitions without a goal.
- Son has been directly involved in five goals in his last three games in all competitions versus West Ham (3 goals, 2 assists).
West Ham hosts Burnley in its next Premier League outing, while Tottenham travels to Wolves in a late kick-off on Saturday.