Liverpool began their Milk Cup Junior Section campaign in impressive fashion by beating County Tyrone 6-0 at a very wet Ballymena Showgrounds on Monday.
Glen McCauley and Curtis Jones each scored two goals, with Stephen Cairns finding his own net and Belfast's Reece McGinley completing the rout.
Zak Rudden scored the only goal as Rangers beat Sheffield United 1-0.
In the Premier Section, County Antrim saw off American side Strikers 3-0 with the help of a double by Thomas Roscoe.
Jack McCourt had broken the deadlock with a low left-foot shot from the edge of the area at the end of the first half, then Roscoe struck twice after the break.
Elsewhere in the Under-17 division, Newcastle United saw off Japanese outfit Higashi Fukuoka 2-0 in Ballymoney, but there were mixed fortunes for the other Northern Ireland county teams.
County Tyrone went down 2-1 to Right to Dream from Ghana, County Fermanagh lost by the same margin to Partick Thistle, and Real Sociedad got the better of County Armagh 1-0.
County Londonderry beat Zambians Lusaka Academy 3-1 and County Down drew 1-1 with Club America.
In the Juniors, AS Roma-USA were joint highest scorers of the opening day thanks to a 6-1 triumph over County Fermanagh in Portrush.
It was a good day for the local sides in the lower age under-15 category as County Antrim, County Down, County Londonderry and County Armagh all recorded victories.
Monday 27 July - Milk Cup Premier Section Results
Right to Dream 2-1 Co Tyrone
OC Blues 2-1 Motherwell
Alset Colombia 2-3 Otago Academy
Co Fermanagh 1-2 Partick Thistle
Vendee 0-1 O'Higgins
Co Antrim 3-0 Strikers
Lusaka Academy 1-3 Co Londonderry
Club America 1-1 Co Down
Newcastle Utd 2-0 Higashi Fukuoka
Malaga CF 1-3 CSKA Moscow
Real Sociedad 1-0 Co Armagh
Monday 27 July - Milk Cup Junior Section Results
Co Down 4-0 Brentford
Sydney Utd 2-0 Dundalk SL
OC Blues 2-3 Co Londonderry
GPS FC Bayern 0-5 Right to Dream
Strikers 2-0 Colina
North Dublin SL 0-3 Co Antrim
Donegal SL 0-1 Plymouth Argyle
Zacatepec 0-3 Southampton
AS Roma-USA 6-1 Co Fermanagh
Swindon Town 1-3 Co Armagh
Co Tyrone 0-6 Liverpool
Rangers 1-0 Sheffield Utd