The Swede played with Bellerin for three years in the Arsenal youth system.
Arsenal conquered Liverpool yesterday at The Emirates in comfortable fashion. Goals from Mesut Ozil, Alexis Sanchez and Olivier Giroud did the job for Arsenal despite a consolation from Jordan Henderson's penalty in the second half.
The man who gave away that penalty was also the man who opened the scoring - Hector Bellerin.
The 20-year-old right-back has come to the fore this season. His curling left-foot finish was his second goal in the Premier League this season and he is looking like an outsider for the Premier League Young Player of the Year award.
Of course, not all the youngsters make it at Arsenal.
One who didn't, despite showing early promise, was Kristoffer Olsson. The young Swede played in the League Cup against West Brom in 2013, scoring in the penalty shootout.
A year later, and with no further appearances to his name, he joined Danish side FC Midtjylland on loan for six months. After impressing, he signed a permanent deal with the club in December.
Now recovering from an unfortunate serious knee injury he was quick to praise his former youth team-mate after his excellent goal yesterday.
Arsenal fans will be hoping there are plenty more Bellerin's coming through the youth system.