Northern Ireland beat China 2-0 in their opening game in the Elite section at the Milk Cup youth tournament.
Josh Doherty headed in the opener on 30 minutes and Mikhail Kennedy turned neatly in the box and fired in the second off the underside of the bar on 45 minutes.
Canada defeated Mexico 2-0 in Monday night's other Elite fixture.
Manchester United secured an 11-0 win over Australian side Gold Coast Academy in the Premier section, with Demetri Mitchell scoring four goals.
Marcus Rashford and Obi Ogochukwu grabbed two apiece and Zachary Dearnley, Travis Johnson and Jordan Thompson were also on target in the Dale Farm-sponsored competition at the Coleraine Showgrounds.
United are defending the title they won in 2013, when Mexico won the Elite category and Everton the Junior section.
Everton drew 2-2 with Middlesbrough in their Junior section opener, while Liverpool saw off Sheffield United 3-1 and Rangers got the better of Co Armagh 3-0.
After Northern Ireland's win at Ballymena, manager Stephen Craigan said he was "really impressed" by the performance of his young side, who now face Mexico on Wednesday night.
"The players have put a lot of work in and winning games gives them confidence," said the former NI international and Motherwell defender.
"We had a gameplan and they took that on board and handled the pressure and expectation well. We earned the right to take our foot off the gas in the latter stages."
The tournament was officially opened by Westlife singer Nicky Byrne, who cut the tape at the Coleraine Showgrounds on Sunday night.
Byrne played in the competition 20 years ago, twice with Dublin club Home Farm and once with Leeds United.
"This is a great honour," said Byrne at Sunday's opening ceremony.
"I played in it back in the day and it was always renowned to be the best youth football tournament in the world.
"It hasn't changed. You have just got to look at the teams that are here again this year."
Northern Ireland 2-0 China
Canada 2-0 Mexico
Chertanovo Academy 1-3 Vendee
Newcastle Utd 2-0 Funabashi HS
RCD Espanyol 1-0 OC Blues
Co Armagh 3-0 Bohemians
CSKA Moscow 3-0 Otago
Brentford 3-2 Lusaka Academy
Partick Thistle 3-1 Craig Bellamy Foundation
Co Londonderry 0-2 Cherry Orchard
Co Fermanagh 0-0 Co Tyrone
Co Down 2-3 Co Antrim
Benfica 0-1 Club America de Mexico
Manchester Utd 11-0 Gold Coast Academy
Brentford 2-0 Watford
Global Premier Soccer 0-1 Dundalk SL
Plymouth Argyle 5-0 North Dublin SL
Co Londonderry 1-1 Motherwell
Santa Marta de Liray 1-4 Co Antrim
Southampton 4-2 Swindon Town
Queen of the South 1-1 Co Down
Japan 2-1 Sydney Utd
O'Higgins FC 3-0 Donegal Schools
SC Corinthians 4-0 Co Fermanagh
Chivas Guadalajara 4-0 Co Tyrone
Everton 2-2 Middlesbrough
Liverpool 3-1 Sheffield Utd
Co Armagh 0-3 Rangers