Sterling made his debut start for Arsenal after transferring from Chelsea on deadline day, scoring a goal in the second half of 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.
“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,” Gunners boss Mikel Arteta said.
Arteta had made seven changes from a Sept 22 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.
“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 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, while Manchester United face Leicester.
AFC Wimbledon or Newcastle, 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.