Saint Anthony's from Kitale won their opening match 1-0 over Shimba Hills in the ongoing 2019 Copa U-19 games at Moi Stadium, Kisumu.
Daniel Musamali struck the lone goal which handed the Rift Valley-based school the hard-fought win over the reigning Coast region champions.
In another end-to-end encounter, Kisumu Day were shocked by a late strike from James Isaboke to hand Ebwali Secondary School the victory.
Mombasa county's Serani High School defeated Goseta from Rift Valley with a 2-0 scoreline at Kisumu Polytechnic.
Goseta were seen as clear favourites but Serani made their dominance count, and six minutes after the break went ahead through Mwinyi Juma. Serani extended their lead through Sufii Mohamed in 51st minute and that was enough to condemn Rift Valley's representative to an opening day defeat.
Bungoma's Koyonzo managed to beat Gatamaiyu School from Kiambu 2-0, with Wellington Andayi opening the score in the 22nd minute before Arnold Bukasa added a second just before half-time.
In the Girls' category, Wiyeta Girls from Rift Valley saw off Nairobi Region representatives Dagoretti Mixed 3-0 in a Group A match.
Jamila Amilda scored twice in the first 24 minutes before Ednah Nanda added a third 10 minutes after the resumption of the second half.
In the other Group A girls' tie, Central Kenya's Njambini won against Ugara from Nyanza 3-0 despite receiving unending attacks from the losers in the last stages of the match. Evaline Anyango scored twice in the 50th and 57th minutes, while Grace Njambi scored the other goal in the third minute.
Nyakach Girls whitewashed their first-day opponents Karugwa 8-1 in a tie held at Kisumu Boys High School. Meanwhile, Rift Valley girls champions defeated Nairobi representatives Dagoretti Mixed Secondary 1-0.