Goals from Liam White, Sos Yao, Tony Stokes and Ollie Allen secured a convincing win for Kevin Keen's younger side in their match at Little Heath.
White and Yao both converted from corners in the first half, while Stokes finished coolly midway through the second half and Allen claimed the goal of the game with a stunning first time strike soon after.
Said Kevin Keen afterwards: "It was a very good, solid opening performance. To score four goals was magnificent and we also defended very well throughout.
"We started the game well, got the two goals before half-time and then carried on where we had left off in the second half. The work-rate was superb and I saw a lot of good things from the players.
"Many of them had experience of playing at this level last season while still schoolboys, and that has clearly prepared them well for this year."
Team: Reed, Andrews, White, Norval, Henry, Yao, Singh, Brady (Davidson 80), Reid (Welsh 60), Allen (Ephrain 68), Stokes. Subs unused: Kemel, Young.
Meanwhile, the under-19s were denied all three points against Boro by a last minute equaliser from the visitors.
Having gone 2-0 up through goals from Greg Pearson and Sam Wright in the first half, Hammers were pegged back as Middlesbrough fought back to draw level in the second half.
Pearson struck what looked to be the winner in the 83rd minute, but Boro - who included many of the team that reached the FA Youth Cup final last season - snatched an equaliser in the final minute to make it honours even.
Said Tony Carr afterwards: "I would have to say it was a fair result in the end. We were quite fortunate to come in 2-0 up at half-time and they dominated much of the second half, so a draw was probably right.
"Having said that, it was still disappointing to concede a goal so late in the game and it would have been a real boost for us to start with a win against a very decent side.
"We played some good football, though, and the players gave their all, so I can't have any complaints."
Team: Behcet, McClenahan, Cohen, Lumsden, Blewitt, Wright, Tucker (Laws), M Noble (Collington), Pearson, Bunce, Cole (Parrington).