The win over France at City Park Stadium, Athlone, was the perfect start to the three match tour of South Africa but with a short turnaround, Wales now face a second game just a couple of days later.
"The win on Friday was a great result against a strong French side," said Wales team manager Phil John.
"It's pleasing to score a few tries but there are always areas to improve on and that's certainly the case going into the game with England."
While Friday's result saw Wales produce a good performance, they've been forced into a couple of changes for the England game.
Lock Rory Thornton and centre Tyler Morgan were both forced off against France with an ankle problem and a bang to the head respectively.
But while Thornton will undergo a late fitness test before the meeting with England, Morgan is definitely out. If Thornton is not passed fit tomorrow morning, Adam Beard will take his place in the second row.
Elsewhere, Garyn Smith takes Morgan's place at inside centre with Torin Myhill coming in at hooker. Josh Helps again leads the side.
Of the replacements named, only eight are available for Lewis to use.
"Injuries aren't ideal but we have confidence in all of our squad and it gives others a chance to impress," said John.
"We're hoping for a repeat performance from the French game."
Wales started with a bang last Friday and were 19-3 up at half time. After France had taken the lead with an early penalty, two kicks from O'Brien and a score from scrum half Tom Williams put Wales in control.
O'Brien converted and added two further penalties for a comfortable interval lead.
Wales, who gave three players their first international caps, used all eight available replacements in the second half but it failed to stop the scoring spree.
Centre Aled Summerhill went over and although France responded with a try of their own, Hewitt's double ended the game as a contest. Replacement Jordan Collier crossed for the final try with O'Brien kicking the rest of the points.
After a convincing opening win, Wales will now be looking to make it two from two against an England side who were narrowly edged out 19-14 by South Africa.
But after England were the winners when the two sides met in Swansea earlier this year, Wales will know they will have to be at their best to get a result.
Wales Under 18 to play England, Outeniqua Park, George. Kick-off 16.00 local time:
15 Steffan Evans (Scarlets) 14 Ashton Hewitt (Newport Gwent Dragons) 13 Aled Summerhill (Cardiff Blues) 12 Garyn Smith (Cardiff Blues) 11 Josh Adams (Scarlets) 10 Angus O'Brien (Newport Gwent Dragons) 9 Tom Williams (Cardiff Blues), 1 Keagan Bale(Newport Gwent Dragons) 2 Torin Myhill (Scarlets) 3 Alex Jeffreys (Newport Gwent Dragons) 4 Josh Helps (Scarlets & Captain) 5 Rory Thornton (Ospreys) 6 Tom Phillips (Scarlets) 7 Oliver Griffiths (Newport Gwent Dragons) 8 Jordan Collier (Ospreys).
Replacements from: Ryan Elias (Scarlets), Leon Crump (Cardiff Blues), Javan Sebastian (Scarlets), Adam Beard (Ospreys), Jon Fox (Ospreys), Dan Brooks (Ospreys), Luke Price (Ospreys), Joe Thomas (Ospreys), Oliver Hitchings (Cardiff Blues), Dan Jones (Scarlets), Luke Garrett (Newport Gwent Dragons).