De Leo has a two-shot advantage as he looks to keep the English Under-18 boys’ open title in Italy’s possession after Andrea Romano’s triumph last year.
De Leo, from Biella Betulle, in Piedmont, dropped a shot at the first, got it back at the second and then relinquished it again at the fifth. Then came six consecutive birdies and he closed with two more for a seven-under-par 65 and a 207 aggregate.
Brown, who had opened with a 73 that included no fewer than six penalty shots, matched his 68 of day two in the third round with a near flawless card.
Two birdies on the way out were followed by three more coming home, a bogey at 10 merely limiting his advantage to four shots over his nearest challengers until De Leo’s superb showing.
Yorkshire have a second challenger in Ben Schmidt (Rotherham) who is tied fifth and seven back of De Leo after scores of 76 67 71.
It is a performance that speaks volumes of the Yorkshire boys’ champion’s temperament as well as his abilities as he has bounced back quickly from having the McGregor Trophy – the English Under-16s’ crown – snatched from him last week by the eventual winner’s four birdies in his closing six holes.
Yorkshire’s other competitors who made the cut are Rotherham’s Charlie Daughtrey (75 73 73), Woodsome Hall’s George Heath (75 73 75) and Fulford’s George Robson (71 76 76).
The difference between the two leaders could be traced to the putter.
De Leo had 26 putts and came off the course commenting “My putter was so good.”
Brown had contrasting fortunes, remarking: “I didn’t hole any putts. A 6ft putt was the longest I made.”
But he certainly wasn’t dismayed. “I’m happy with the result. I knew someone would shoot a good score and I just wanted to keep myself in it, to stay as close as I could to the lead.”
He is all the more pleased with his position having found himself three over through nine holes of the first round.
Alluding to his six penalty shots, he joked: “I only actually hit 67 shots that day.”
The other big mover of the day was Matt Freeman (Notts), who started the third round seven shots off the lead and tied 35th.
He went out determined to close the gap and returned asix-under 66 to share third place on three under.