A second successive 66 saw the Glaswegian end the second day as the surprise leader on 12 under par, one stroke ahead of the English duo of Ross Fisher and Matthew Southgate, Dane JB Hansen and America's Peter Uihlein.
The 35 year old, who has just a single top ten finish to his name on The European Tour, carded five birdies, a solitary bogey and an eagle three at the par five 12th hole at Castle Stuart Golf Links, in Inverness.
Doak relinquished his playing privileges at the end of his only previous season on The European Tour, in 2009, but returned to the top tier last year courtesy of a tenth place finish in the Challenge Tour Rankings.
Some tuition from Torrance, the 81 year old father of Ryder Cup-winning Captain Sam and the man who coached Padraig Harrington to three Major Championships, has finally seen Doak begin to realise his undoubted potential.
"It's absolutely phenomenal to shoot 66-66 in the first two days," he said. "You start the week thinking you want to go low, but to actually do it is fantastic.
"I feel it has been coming all year, but just maybe haven't put it all together. These two days, I've definitely put it together.
"It helps Bob being here, as well. He's not at many tournaments now, so it definitely makes a difference when he is."
Doak also thanked the home crowds, who have shown their support over two sun-kissed days on the Moray Firth.
"It's fantastic, to hear all the highland accents up here cheering you on," he said.
"I'm sure there will be a big following at the weekend. People are up for it, so hopefully a lot more will come."
Uihlein, who recently won the Madeira Islands Open, recovered from an early double bogey with eight birdies "“ six of them in a back nine of just 30 "“ to sign for a round of 66 and an 11 under par halfway total.
He said: "It was a bad start, but then got it going a little bit. I made a good birdie on 16 and then another one on 18, and then I really got lucky on the second.
"I blocked it way right but had a clean lie, hacked it out and made a nice 15-footer for birdie, and was off and running from there. My swing started feeling a little bit better, and coming in it started to feel much better."
Uihlein's compatriot Phil Mickelson enters the weekend four strokes off the pace after an up-and-down round of 70.
He said: "I was a little bit off today, and I started out with another three putt from 20 feet. But I think the reason why today was a good day is because I was off but I fought hard, I shot a couple under and I'm in a position where if I can get a hot round going, I can make up ground and I'm playing well enough to do it."
Richard Green was the only Australian to make the cut, the Victorian in 46th position at 5 under and seven shots from Doak.
Leading second round Scores:
132 C Doak (Sco) 66 66,
133 J Hansen (Den) 68 65, P Uihlein (USA) 67 66, M Southgate (Eng) 69 64, R Fisher (Eng) 68 65,
134 L Gagli (Ita) 67 67, J Morrison (Eng) 66 68, S Khan (Eng) 65 69, H Stenson (Swe) 70 64, V Dubuisson (Fra) 68 66,
135 C Paisley (Eng) 70 65, F Molinari (Ita) 69 66,
136 R Derksen (Ned) 67 69, G Mulroy (RSA) 69 67, N Fasth (Swe) 70 66, P Mickelson (USA) 66 70, J Parry (Eng) 64 72, T Olesen (Den) 67 69, R Sterne (RSA) 67 69, D McGrane (Irl) 67 69, D Horsey (Eng) 69 67, M Siem (Ger) 67 69, B Grace (RSA) 71 65,
137 C Lee (Sco) 68 69, M Ilonen (Fin) 66 71, L Slattery (Eng) 71 66, M Laird (Sco) 68 69, T Jaidee (Tha) 66 71, J Van Zyl (RSA) 68 69, P Casey (Eng) 70 67, M Madsen (Den) 70 67, T Fleetwood (Eng) 70 67, C Lloyd (Eng) 68 69,
138 N Colsaerts (Bel) 70 68, S Henry (Sco) 69 69, J Lagergren (Swe) 71 67, B Koepka (USA) 70 68, B Wiesberger (Aut) 68 70, R Gonzalez (Arg) 70 68, S Kjeldsen (Den) 69 69, S Benson (Eng) 69 69, R Jacquelin (Fra) 68 70, G Bourdy (Fra) 68 70, E Pepperell (Eng) 69 69, C Wood (Eng) 68 70,
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