If the circumstances were right, D.C. United Coach Ben Olsen would have gone full force into the CONCACAF Champions League opener Wednesday night at RFK Stadium. United was, after all, dipping into international competition for the first time in five years as the favorite in a three-team first-round group.

But Olsen also had to consider his squad’s health and welfare amid a congested MLS schedule. So he rested his regulars and put his faith in a largely secondary crew, which manufactured a 1-0 victory over Waterhouse FC of Jamaica.

The only usual starter in the lineup, forward Eddie Johnson, scored in the fifth minute before a crowd of 3,330.

“These games are never perfect, but it’s about the result and starting the team off on the right foot in this tournament,” Olsen said. “You would like to get maybe another goal or two but ultimately a win in a four-game series is pretty good.”

United will play Waterhouse in Kingston, Jamaica, on Sept. 16, then face Tauro of Panama home and away. The group winner will advance to the quarterfinals in early 2015.

United is among five MLS clubs in a tournament featuring 24 teams from North and Central America and the Caribbean.

D.C. qualified by winning the U.S. Open Cup in 2013, the silver lining to a disastrous regular season campaign.

Johnson returned to the lineup after serving the first of a two-game MLS suspension Sunday vs. the Colorado Rapids. The ban applies to league matches only, so he played Wednesday and will sit again Saturday when United visits first-place Sporting Kansas City.

The rest of Olsen’s selections were reserves. Goalkeeper Joe Willis and defender Conor Shanosky, both on loan to third-division Richmond most of the season, performed well in their first appearances of the year.

Defender Kofi Opare made his D.C. debut since arriving three weeks ago. Midfielder Alex Caskey lined up at left back, center back Nana Attakora on the right.

The midfield corps of Jared Jeffrey, Kyle Porter, Collin Martin and Lewis Neal had combined for eight regular season starts (six by Neal).

At the start, the second unit was first rate. Shanosky delivered a wonderful long ball that carried some 60 yards. Newcomer David Estrada tracked it down near the end line and one-timed a cross to Johnson at the edge of the six-yard box for a one-timer an instant before goalkeeper Richard McCallum could intervene.

The early goal “hindered us a little bit because up until that point we were really good,” Neal said. “We started off really well, but then when we got the goal, we sat back and let them dictate the game a little bit.”

Waterhouse created danger before halftime, most notably Jermaine Anderson testing Willis with a turn and tight-angled effort from eight yards. In the second half, the Jamaican side set the pace and, with a series of promising build-ups, seemed on the cusp of an equalizer.

“Their goal upset us a little bit,” Waterhouse Coach Anthony Patrick said, “but we kept playing.”

Willis made a diving save on Kenardo Forbes’s 22-yard bid in the second half, but United managed the game well until Waterhouse’s late bids: Vincent Earle’s 25-yard drive swerved wide of the left post and Juvaune Benjamin’s long-range effort was stopped by Willis.

“It’s a confidence boost,” Willis said, “but also gives us a good quick start and puts us in a good spot for the rest of the group.