Captain and full back Dafydd Howells, who has already turned out for Neath in the Premiership, led the way with a hat trick of tries, Josh Adams, Dan Jones, Rhys Williams and Torin Myhill also running over for scores. Dan Jones slotted four conversions for a match tally of 13 points and Luke Price also added a conversion.
Wales defence coach Shaun Edwards had worked hard with the group since the Scottish game, with a clean sheet just rewards for players and staff.
Lewis said, "After reviewing the Scotland game we concluded we didn't need to change the way we played, but to execute that approach better. We continued to challenge the opposition with ball in hand and produced a quick tempo game which produced some very satisfying tries.
"The work Shaun Edwards has done defensively certainly bore fruit in not conceding any tries and with an extremely high tackle completion rate."
Georgia beat Italy to set up a clash with the Eastern European side on Saturday.
"Georgia have made great strides in recent years. They pushed Ireland very close in the first game and saw off Italy on Tuesday. They will be a different proposition to Portugal. We need to continue to impose our style of play on the game which will hopefully create some try scoring opportunities.
"We are pleased with the level of exposure all the players have had so far and the way they have all responded to that which has given us some selection headaches ahead of Saturday's game."
Wales U18 (v Portugal): Dafydd Howells (capt, Ospreys); Josh Adams (Scarlets), Garyn Smith (Blues), Tyler Morgan (Dragons) (Joe Thomas Ospreys 40), Rhys Williams (Exiles); Daniel Jones (Scarlets) (Luke Price Ospreys 41), Tom Williams (Blues) (Daniel Brooks Ospreys 41); Keagan Bale (Dragons) (Robert Lewis Blues 41), Ryan Elias (Scarlets) (Torin Myhill Scarlets 41), Dillon Lewis (Blues) (Alex Jeffries Dragons 41), Gareth Allen (Dragons) (Adam Williams, Ospreys, 55), Rory Thornton (Ospreys), Tom Phillips (Scarlets), Matthew Marley (Blues), Jonathon Fox (Ospreys)
Wales scorers: Tries: Dafydd Howells (3), Josh Adams, Dan Jones, Rhys Williams, Torin Myhill.
Cons: Dan Jones (4), Luke Price. Y/C: Tom Phillips (74)