VIENNA, July 26, 2012 (AFP) - Despite the crack of dawn start, Olesen, who was in contention on the final day of last week's British Open, picked up where he left off with a birdie at the 17th hole to move to eight under par.
That put him level with Larrazabal, who posted a flawless round of 64 either side of the three hours and 40 minutes rain delay on Wednesday.
Buoyed by his showing at Lytham, where he partnered world No.2 Tiger Woods in the third round, the 22 year old is now confident of doubling his tally of European Tour titles.
"Obviously my confidence is high after last week, and I've been shaping my irons very well recently" he said.
"You can be really aggressive with your approach shots here because the greens are so soft, but they're rolling really well and the course is in great shape considering how much rain we had."
Frenchman Thomas Levet also shrugged off any lingering lethargy to move to seven under par 65 courtesy of a tap-in birdie at the 18th hole. He stands level with David McKenzie of Australia and Will Besseling of the Netherlands.
Larrázabal, meanwhile, will return to the course at 1:50 p.m. after all second round tee times were pushed back an hour.
Collated first round scores in the Austrian Open on Friday:-
(Britain and Ireland unless otherwise stated)
(Par-72)
64 - Thorbjorn Olesen (DEN), Pablo Larrazabal (ESP)
65 - Wil Besseling (NED), David McKenzie (AUS), Thomas Levet (FRA)
66 - Mikael Lundberg (SWE)
67 - Felipe Aguilar (CHI), David Higgins
68 - Oliver Wilson, Alastair Forsyth, Oscar Floren (SWE)
69 - Richard Bland, Craig Lee, Augustin Domingo (ESP), Daniel Denison, Thomas Norret (DEN), Niclas Fasth (SWE), Andrea Pavan (ITA), Victor Riu (FRA)
70 - Joakim Haeggman (SWE), Steve Webster, Paul Waring, Joakim Lagergren (SWE), Mathias Gronberg (SWE), Kenneth Ferrie, Peter Hedblom (SWE), Rikard Karlberg (SWE), Emiliano Grillo (ARG), Joel Sjoholm (SWE), Stephen Dodd, Taco Remkes (NED), Shane Lowry, Gregory Bourdy (FRA)