The Australian lashed his drive at the monster 629-yard par-five ninth (having started on the back nine) into rough on the right, but hacked out into semi-rough on the left 136 yards from the pin. A wonderful approach shot then left him with an 18-inch putt for birdie.
That was his seventh birdie, with only a bogey five on his 14th hole spoiling his card.
Scrivener is one of four players tied for third behind England's Alex Fitzpatrick and Spain's Alfredo Garcia-Heredia.
Level with Scrivener are England's Matt Wallace, Henrik Norlander (Sweden) and Dean Huizing (Netherlands). Local amateur Nicola Gerhardsen is one of seven players a shot further back.
Fitzpatrick's brother Matt, the former US Open champion who won this title in 2017 and 2018, returned a four-under-par 66 as the early starters battled cold and wet conditions.
"Happy with a good start, I would have taken it this morning when I woke up and it was pouring," he said.
"It's one of my favourite places to be but it wasn't really this morning. It was horrible; warming up in the rain and you get out there and it's pouring, you don't feel like the ball is going very far.
"Fortunately with that the greens are a little bit softer so you can be a bit more aggressive but it was quite tricky."
Wallace added: "It was tough. I have never played this course when it was like this, wet, windy and cold, but I played really nice."
with PA
