The newly-promoted South West One club overcome Kingsbridge 22-12 in a hard-fought and competitive match at the Rectory on Friday evening.
Services led 10-0 at the break thanks to two tries within two minutes midway through the first half by Phil Greenside and the impressive Rhys Williams, who finished off a great move down the left.
Kingsbridge, who had played Ivybridge at the weekend, came back after the break and went 12-10 in front with Jake Vincent and Dave Evans crossing the whitewash.
Devonport, who used the match to give 28 players a run-out, lost their way slightly for a little bit in the second period, but they finished strongly and late tries by Joe Page and another stunning effort by Williams secured them the win.
“We said at the end had we lost 12-10 we would have got just as much out of the game,” said Lewis. “The result just makes it look good in the paper.
“The main thing is we got out of it what we needed. It was our first run-out and their second.
“We had 13 players on the bench. Our intention was to swap 10 at half-time and bring the other three on a bit later on. There were players playing in new positions and stuff like that and we just wanted to see how they want. And I think it went really well. In the end, though, we did have to make a couple of extra changes as because of a couple of niggling injuries.”
He added: “They (Kingsbridge) had a reasonable side out. The thing is they have a big, lumpy pack and that is what we are going to come up against for the whole of this season, especially with the Bristol and Gloucestershire teams. We have to learn how to combat that and how to break them down and I think we did that really well.”
Services will continue their pre-season preparations next Friday when they host South West Premier League side Ivybridge at the Rectory (7.15pm).