Despite the comfortable winning margin the 20-year-old, who also featured in England's Under-20 Six Nations winning campaign earlier this year, was most pleased with how the side kept their tryline intact in La Roche-sur-Yon
"We're obviously pleased to get the win against a tough France side," Day told the RFU Podcast. "It was a tight first half but we managed to pull away in the second half with a couple more scores. I also thought our defence was pretty outstanding at the end to keep them out."
They may have overcome French home advantage, but it doesn't get any easier for Nick Walshe's youngsters who now face reigning champions South Africa - themselves fresh from a 97-0 mauling of the USA.
Though England are wary of their dangers, Day was keen to impress that they would look to give the Baby Boks plenty to think about themselves in Sunday's encounter.
"It's another massive game against the champions and we saw them put almost 100 points on the USA as well. We're going to have to be at our best, but equally they'll have to be at their best to stop us. We're confident and it's all to play for."
One of four Saints currently in Western France, Day also found time to praise clubmate Danny Hobbs-Awoyemi's contribution, while showing encouragement for the pair waiting in the wings.
"Hobbsy was brilliant when he got on and I think that Will and Stevo were unlucky not to be involved," he added. "They'll be pushing hard and there will be plenty more opportunities."