The inaugural entry of the under-18 team into the Sydney Junior Rugby Union competition was marked with a tightly contested match against Sylvania.

Bowral won the match with Charlie Machado scoring on the final bell to seal the win.

Sam Clark was successful with the conversion.

There was plenty of celebration for the Blacks after the match with the Sydney competition a big step up for the team.

Blacks coach Paul Frena said Sylvania were known as a side that would test a team's discipline and it was a credit to the Bowral players that they stayed focused on the game plan in spite of strong provocation.

He said discipline, focus, aggressive defence and dominance at the set piece laid the foundation for victory.

Bowral led 12-5 at halftime.

In the second half Sylvania rallied and led 18-15 with a minute to go.

Bowral won a scrum near the Sylvania line, recycled the ball and moved to the right where Machado raced to the corner and scored to win Bowral the match.

The final score was 22-18.

Bowral has stepped up to the Sydney competition as a result of Illawarra not having an under-18s competition this year.

"Playing in Sydney provides this strong cohort from Bowral the pathway needed to keep them engaged with rugby and build into Colts and grade," Frena said.

In round two of the competition Bowral will take on Forestville this Sunday, April 10 at Eridge Park with kick off at 12pm.

Bowral seniors will also be at home this weekend.

Kick off for second grade will be 1.30pm and first grade at 3pm.