The 50 year old, making his second Qualifying School appearance, missed out on one of the five coveted cards in 2017 after a three-man play-off, but has returned to Portugal in a bid to secure playing rights on the Staysure Tour in 2018.
Shacklady started his round from the tenth hole, and made consecutive birdies on the 15th and 16th holes, cancelling out an earlier bogey.
After starting the day two under par, he reached a total of five under par after further gains on the second and third holes, but undid his hard work with a bogey and double bogey on the fourth and fifth holes.
Shacklady recovered strongly and birdied the final two holes for a four under par total, two strokes ahead of compatriot Paul Streeter and Argentina’s Mauricio Molina.
“I’m very pleased that I showed some bottle out there,” said Shacklady. “On the fifth hole I found the bottom ridge of the green, lipped out for two and then missed the next two putts. I had to have a word with myself after that and calm myself down.
“I said to my wife last night that everyone is going to have moments on this golf course, I just hope that was mine. It’s very easy to become negative. You have to commit to everything out there, but it’s easier said than done. It’s mentally gruelling. When it’s fiery, fast and windy out there, it’s no fun.
“I’m just pleased I didn’t lose it towards the end, it can drown you when you have moments like that. I refocused and started again. I’d have been pleased finishing level par today, but to come in with two birdies is great.
“It’s nice having the cushion at the top of the leaderboard, but I was in the same scenario last week at First Stage. I was coasting and only finished second. You have to play this like it’s a tournament and try to win it.”John Kemp
Making up the top five are English amateur John Kemp and Gary Wolstenholme, a six-time Walker Cup player and two-time Staysure Tour winner, on level par.
Kemp, a member of Woburn Golf Club, host course of the Travis Perkins Masters, carded one of the lowest rounds of the day, a four under par 67.
“It is very hard to judge how you are as a player when you go up against the pros,” said Kemp. “At First Stage, I didn’t play very well on my first nine holes, but I played the next 27 in six under par – which was good golf for me.
“I now know I can compete at this level. I played well in patches and had a couple of breaks to get me back up the leaderboard. I played with a bit more freedom today, I did hit some bad shots in the middle of my round but I knuckled down in the end.”
Players within eight shots of fifth place will make it through to Thursday’s final round on the Vale da Pinta Course at Pestana Golf Resort, with the top five earning cards for the 2018 Staysure Tour season.