The Harlequins full-back, who had not crossed the whitewash for England before the tournament began, scored four tries, had 65 carries and beat 25 defenders, conceding no penalties and gaining 540 meters.
Brown's showing continued his fine form from the autumn and after finally getting a run at full-back rather than wing, the 28-year-old believes Lancaster's management style has brought the best out of him.
"Stuart is great in that he will give you the opportunity if you deserve it," he said.
"That's what he has done for me. He gives you belief by giving you a chance. He's stern but fair. He can seem quite distant but once you talk to him one-on-one he's a brilliant bloke.
"Even from the autumn we've moved on with our attack. Defence is still at a world-class level but our attack has come on leaps and bounds and has still got room to get better."