Silhillians booked their place in the final of the Warwickshire Colts Cup in front of a bumper crowd at Copt Heath.
Sils started the semi-final strongly with Louis Roach opening the scoring after five minutes with the try converted by Dom Marks.
Marks increased the lead to 10-0 midway through the half with a well-taken penalty.
Rugby Lions then had a period of pressure on the Sils line and were duly awarded a penalty on the stroke of half-time to take the score to 10-3 at the break.
In the second half Sils applied consistent pressure and eventually broke through, scoring two tries through Callum Bradbury and Toby Wassell, which were both converted.
Lions scored a late consolation try but Sils will now play Barkers Butts in the final at Butts Park Arena, Coventry RFC, on Monday (7.30pm).