Varndell was among the seven try-scorers as the Saxons beat hosts USA 56-17 to book a place in the final.
His Tigers teammate Johne Murphy was a try-scorer for Ireland A as they reached the final with a 40-5 win over Georgia in their final pool match and Varndell says the Saxons will have to improve ahead of Saturday’s game.
Varndell said: “We have to step up from this week going into next week. We conceded two tries so we need to focus on the good points from today's match and take that forward.
“USA are a great team and they are improving all the time. Their passion and commitment is there, they exposed us in areas today especially in that first try.”
Tigers prop Dan Cole was given a late call-up to the Saxons starting XV after injury to Tom Mercey, while Varndell started on the wing and Ben Woods was named in the pack. Matt Smith replaced Varndell from the bench with 10 minutes remaining.
England Saxons: Nick Abendanon, Noah Cato, Dominic Waldouck, Brad Barritt, Tom Varndell, Stephen Myler, Micky Young; Dan Cole, Rob Webber, David Flatman, Peter Short, Nick Kennedy, Phil Dowson, Ben Woods, Tom Guest
Replacements: Mark Lambert, Neil Briggs, Chris Jones, Luke Narraway, Joe Simpson, Danny Cipriani, Matt Smith