Raheem Sterling scored his first Arsenal goal and Jack Porter became the club's youngest ever starter in a 5-1 rout of Bolton in the League Cup on Wednesday, while Liverpool reached the last 16 with a 5-1 win against troubled West Ham.
Sterling marked his maiden Arsenal start following his transfer deadline day move from Chelsea with a second-half strike in the third-round tie at the Emirates Stadium.
The 29-year-old will hope his goal marks the start of a career revival after a disappointing two-year spell at Chelsea.
Gunners boss Mikel Arteta had made seven changes from Sunday's stormy 2-2 draw at Premier League champions Manchester City, including giving goalkeeper Porter his record-breaking debut in place of the injured David Raya.
Aged 16 years and 72 days old, Porter was the youngest player ever to start for Arsenal, surpassing the previous record holder Cesc Fabregas, who was 16 years and 177 days when he played against Rotherham in 2003.
Porter was Arsenal's second youngest ever player overall after Ethan Nwaneri, who was 15 years and 181 days, when he made his debut in 2022.
Declan Rice put Arsenal ahead in north London after 16 minutes with a clinical finish from the edge of the area for his first goal this season.
Fittingly on Porter's record setting day, it was Nwaneri who doubled Arsenal's lead in the 37th minute with his first goal for the club.
The 17-year-old forward celebrated his first Arsenal start with a close-range finish from Sterling's cross.
Nwaneri struck again four minutes after half-time with a composed strike from 12 yards.
Porter had to pick the ball out of the net for the first time in his Arsenal career in the 53rd minute when Aaron Collins jinked around him and slotted into the empty net.
Sterling netted in the 64th minute, tapping in after Saka's cross was spilled by Bolton keeper Luke Southwood, and Kai Havertz grabbed the fifth from close range in the 78th minute.
West Ham in turmoil
At Anfield, Diogo Jota and Cody Gakpo scored twice as Liverpool's understudies demolished West Ham to increase the scrutiny on Julen Lopetegui.
Under pressure after winning only one of his first five league games since replacing David Moyes, former Real Madrid chief Lopetegui made eight changes from the 3-0 defeat against Chelsea last weekend.
Despite spending $159 million on new signings, Lopetegui was jeered by furious fans on Saturday after becoming the first West Ham manager to suffer three consecutive losses at home to start a season.
The Hammers took a surprise lead in the 21st minute as Kostas Tsimikas's miscued clearance deflected in off Liverpool defender Jarell Quansah for a farcical own goal.
Reds manager Arne Slot had made nine changes from Saturday's win over Bournemouth as Italy forward Federico Chiesa made his first start since his move from Juventus.
And Jota equalised four minutes later, the Portugal forward out-jumping West Ham keeper Lukasz Fabianski to nod in Chiesa's volley.
Jota struck again in the 49th minute as he exchanged passes with Curtis Jones and drilled past Fabianski.
Mohamed Salah came off the bench to score in the 74th minute with a simple finish after Alexis Mac Allister's shot was pushed into his path.
West Ham were in disarray and Edson Alvarez was sent off in the 76th minute for a second booking after chopping down Salah.
Capping another torrid day for Lopetegui, Gakpo smashed home from 18 yards in the 90th minute and then guided a deflected effort beyond Fabianski moments later.
