Arsenal manager Mikel Arteta was full of praise for Raheem Sterling after the on-loan forward scored his first goal for the club in a 5-1 League Cup victory over Bolton Wanderers, while Liverpool thrashed West Ham United by the same score.
Sterling marked his first 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 England international will hope his goal marks the start of a career revival after a disappointing two-year spell at Chelsea.
"He was great. He's started to show glimpses of what he can do. Physically, he needs to get to the level we require, but it was a massive step today," Arteta said.
Arteta made seven changes from Sunday's stormy 2-2 draw at Premier League champions Manchester City, including giving goalkeeper Jack Porter his record-breaking debut in place of the injured David Raya.
Age 16 years and 72 days, Porter became the youngest player 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 player overall after Ethan Nwaneri, who was 15 years and 181 days, when he made his debut in 2022.
"Jack has been training with us since pre-season. He reacted really well and was really composed. What an experience," Arteta said.
Arsenal will travel to Championship side Preston North End in the last 16, with the tie of the fourth round pitting Tottenham against Manchester City.
Liverpool's bid to retain the trophy will continue at Brighton & Hove Albion, while Manchester United face Leicester City. AFC Wimbledon or Newcastle United, whose tie was rearranged due to flooding at the League Two side's stadium, will host Chelsea.
Declan Rice put Arsenal ahead after 16 minutes with a clinical finish from the edge of the area for his first goal this season. Nwaneri, 17, doubled Arsenal's lead in the 37th minute with his first goal for the club and struck again from 12 yards four minutes after half time.
Porter had to pick the ball out of the net in the 53rd minute when Aaron Collins jinked around him and slotted home. Sterling netted in the 64th minute, tapping in after Bukayo Saka's cross was spilled by Bolton keeper Luke Southwood, and Kai Havertz grabbed the fifth from close range in the 78th minute.
Liverpool pile more misery on West Ham
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, Lopetegui made eight changes from the 3-0 defeat against Chelsea last weekend. That loss made Lopetegui the first West Ham manager to suffer three consecutive defeats at home to start a season.
The Hammers took a surprise lead in the 21st minute as Kostas Tsimikas' miscued clearance deflected in off Liverpool defender Jarell Quansah for a farcical own goal.
But Jota equalised four minutes later, the Portugal forward out-jumping West Ham keeper Lukasz Fabianski to nod in Federico Chiesa's volley. He 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.
"We don't deserve this score because we did a lot of good things. They scored an offside goal. I'm sorry for our fans," Lopetegui said.
Liverpool boss Arne Slot added: "Since I've been here it's never been easy, although sometimes the result looks different."
