The Spaniard hit nine birdies in his impressive opening day’s work, including four straight from the ninth.
"I played very consistent all day long and gave myself a lot of birdie chances," Velasco, 30 and twice a winner on the Challenge Tour, said.
"It's been a long time since I played this well. I didn't realize I had four birdies in a row as I was just so focused."
Velasco was two shots clear of chasing pack of six men, including Britain’s Oliver Wilson, who hit six birdies in his 66.
Wilson was joined on six-under with Tommy Fleetwood, Ben Parker, Morten Orum Madsen, Magnus Carlsson and Joakim Largergren.