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 Fàbregas – 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.

Arsenal will next face EFL Championship side Preston in the fourth round.

Meanwhile, 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 US$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.

Liverpool next face Brighton in the fourth round. (AFP)