The Barcelona forward opened his international account in Egypt's match against Sudan on Tuesday, just two weeks after renewing his contract with the Catalan club.
It took Abdelkarim only five minutes to find the net after coming off the bench.
The young striker was introduced in the 87th minute in place of Omar Marmoush and quickly made his mark, scoring his first senior international goal just moments after entering the pitch.
Abdelkarim had already made appearances for Egypt at the World Cup during the summer, but had been unable to find the net for the senior side.
That changed against Sudan, giving him another significant moment during a year in which his profile has continued to grow.
The goal also placed Abdelkarim among the youngest players to score for Egypt's senior national team.
He is now the third-youngest goalscorer in the country's history, behind only Abdel Karim Sakr and former Ajax and Tottenham striker Ahmed Hossam Mido.
The milestone comes during a particularly significant period in Abdelkarim's development.
Barcelona announced his contract renewal on September 11, before the forward formally signed his new agreement alongside club president Joan Laporta four days later.
His first senior international goal therefore arrives only weeks after securing his future at club level.
Abdelkarim has continued to make progress within the Barcelona setup during 2026, increasing his involvement around the first team while also establishing himself as one of the emerging names in Egyptian football.
The goal against Sudan adds another important step to that development.
His contribution was particularly efficient given the limited time available to make an impact. Abdelkarim entered the match with only a few minutes remaining and needed just five minutes to turn his appearance into a landmark moment.
It also gives him a first senior international goal after previously featuring for Egypt without finding the target.
The timing means September has become a month to remember for the young forward.
He began it with a new Barcelona contract and ended it by scoring his first goal for Egypt.
The latest achievement adds to a year in which Abdelkarim has continued to increase his standing at both club and international level.
At just 20, the Barcelona forward now has his first senior international goal to accompany his growing role with his club and his experience at a major international tournament.
For Egypt, it provides another glimpse of a young forward who is continuing to make progress at senior level.