Scotland's Marc Warren set the clubhouse target on the second day of the weather-affected inaugural NH Collection Open at La Reserva de Sotogrande.
A delay of two hours and 40 minutes on Thursday due to heavy rain meant half the field were unable to complete their opening rounds on schedule, while 45 players had not finished round two before play was suspended due to darkness.
Earlier in the day, Warren had completed an opening 72 before adding a second round of 67 containing six birdies and just one bogey.
Damien McGrane leads the Irish challenge on one-over after his round of 69, while Kevin Phelan is three shots further back with Simon Thornton on three-over.
"My round didn't finish yesterday so I had to come back and play seven holes this morning and I played okay," the two-time European Tour winner said.
"At the start of the second round I struggled a bit with concentration, but once I got it going I played really good - long game was excellent, short game was good. I think I got the best out of my round today.
"Today and yesterday's conditions were pretty similar, obviously without the rain. The wind is going to stay pretty strong and it's going to be tough for the guys playing this afternoon.
"I have been playing well the last few weeks, getting stronger and stronger, so I was really looking forward to this event. It's like a bonus event for us, coming at the last minute, and I am pleased to see how good the course actually is. I'm looking forward to the next two days.
"I like the course very much. If it was perfect weather it would still be a good test, but with the strong winds we have here it gets really tough at times."
At five under par, Warren shared the lead with England's David Horsey, who had three holes of his second round to complete. Play is scheduled to resume at 8am BST on Saturday.
Chile's Felipe Aguilar was safely in the clubhouse on four under after a 69, while Spain's Adrian Otaegui and Welshman Bradley Dredge were also four under with three and six holes to play respectively.
First round leader Jack Doherty added a 74 to his opening 69 to finish one under par.
Local favourite Alejandro Canizares, who was looking for back-to-back wins after his victory in Morocco, was in danger of missing the cut at six over par with three holes remaining, the Spaniard having taken a quadruple-bogey nine on the par-five 11th.