Michael Hoey was the best of the Irish competing at the Portugal Masters on Thursday as South Africa's Louis de Jager opened up a two-shot lead after the first round in Vilamoura.
De Jager registered eight birdies in his bogey-free eight-under-par 63, including five in his first seven holes.
The 32-year-old started the week 123rd in the Race to Dubai rankings as he looks to end Sunday in the top 117 and maintain his playing privileges for 2020.
De Jager's compatriot Justin Walters, Englishman Oliver Fisher and Australia's Jake McLeod are all on six under.
Walters and Fisher - who produced the first 59 in European Tour history with his second round at this event last year - are 121st and 112th in the Race to Dubai respectively, while McLeod is 159th.
Hoey carded a one-under 70, one shot better than Paul Dunne. Padraig Harrinton is two-over with Gavin Moynihan on three-over-par.
After shooting a 65 featuring seven birdies and a bogey on Thursday, Fisher was quoted on europeantour.com as saying: "I'm just trying my best.
"The best thing I can do is go out there and be clear about what I'm doing and not let my mind wander too much and think 'what if'.
"It's a week I like and a course I like. I'll go out and give it my best and stay in the moment as much as I can and see what happens.
"I actually played really well today but it's funny to think I had to be six shots better to do that (59) again. It was a great day. This course has given low scores over the years - anything is possible out there. It's nice to go out there with a bit of expectation after that good round last year."
A group of seven players are a further shot back, including a pair of Fisher's compatriots - Matthew Southgate and David Horsey.
The others on five under are Italy's Renato Paratore, South Korea's Jeunghun Wang, South African duo Darren Fichardt and Brandon Stone and the USA's Sihwan Kim.