Albion find themselves behind to Hakim Ziyech's precise strike just before the half hour mark but it was against the run of play and Lamptey, 21, has been a constant threat as Albion dominated the first-half.
A stand-out moment came when the former Chelsea man won the ball off Callum Hudson-Odoi before dancing past a midfield inclduing FIFA Pro World XI stars Jorginho and N'Golo Kante.
Here's how fans reacted on Twitter:
@ryanadsett: "I love Tariq Lamptey."
@CFC_Raf: "Swear Tariq Lamptey always turns into Dani Alves when he plays us."
@Martindockray2: "Quality player, big clubs will come knocking no doubt."
@johnmead134: "Why on earth did Chelsea let him go?"
@_lucasglory: "What a player."
It comes as no surprise that Lamptey has reportedly been named on the shortlist for a number of the country's elite clubs this transfer window — but Brighton won't be letting him go in a hurry. Chelsea will be wondering why they did.