But Biggar, and Coach Patrick Horgan, are looking for better accuracy and execution when they face Japan at the Liberty Stadium tomorrow night (Tuesday).
Biggar said, "We would have bitten off your hand at the start of the day had you have said we would finish the night with a four-try win. Having said that, we wanted to score more tries than that and we would hope to do so in our next game.
"It's tough when so much is expected of you, but to be honest we are glad to get that first one under our belt."
Horgan has made 10 changes for the game against Japan but expects no less a performance from his players. "There is no reason for these players not to perform - all 26 players in the squad are capable of earning their place in the side to face France," said the coach.
"We had a number of missed try-scoring opportunities against Italy so we have been working on our execution and accuracy ahead of the Japan game. However, Italy's defence was excellent and certainly kept them in the game.
"You are always looking for improvement but we are quite pleased overall with our first performance. Japan gave a good account of themselves against France and we will certainly give the side the respect they deserve.
"The crowd supported us well on Friday night and we hope we can give them something more to shout about against Japan - and again on Saturday against France."
In the other game in the Pool, France will be looking to build on Friday's victory over Japan by beating Italy at 5.00pm to set up a potential winner-takes-all encounter between Wales and France at 5.00pm on Saturday.
Wales Under 20 team v Japan: Jason Tovey (Dragons); Leigh Halfpenny (Blues), Luke Ford (Blues), Rhys Williams (Scarlets), Nathan Rees (Blues); Dan Biggar (Ospreys), Gareth Williams (Ospreys); Sam Hobbs (Blues), Ryan Prosser (Bristol), Scott Andrews (Blues), Ashley Sweet (Dragons), Jevon Groves (Blues), Lloyd Phillips (Scarlets), Justin Tipuric (Ospreys), Sam Warburton (Capt, Blues)
Replacements: Rhys Lawrence (Ospreys), Ryan Bevington (Ospreys), Patrick Palmer (Blues), Josh Turnbull (Scarlets), Jonathan Davies (Scarlets), Rhys Webb (Ospreys), Gareth Owen (Ospreys)
Tickets for all Junior World Championship match days are £2 for children and £8 for adults and are available at all match venues right up until kick-off.