Since partnering Padraig Harrington to two wins against the Americans, however, he has managed only one top five finish and finds himself down at 140th in the Official World Golf Ranking.
Earlier it had looked like being Padraig Harrington's morning at Oceânico Victoria when he went two clear with six birdies in his first 11 holes.
But in a real mixed bag of a finish the 41 year old Irish star, without a European Tour victory for over four years, had a double bogey, two more birdies and two bogeys, both of those coming when he three-putted.
“I didn't really push on,” admitted the three-time Major Champion. “I made a few mistakes.
“It was all going very nicely and I made a couple more birdies after the double bogey, but I’m a bit upset about the two three-putts at the end.
“That was a pity because eight under would have been a nice return, six under for the round, eight under for the tournament, and I can forget about the double bogey. But as I say the two 3 putts are the ones that hurt a lot more.”
Wiesberger had five birdies and an eagle two at the 315 yard 15th, his sixth.
The Vienna golfer's lone dropped shot came at the difficult seventh, where his drive picked up mud and his approach finished in the greenside bunker.
“I'm feeling good,” said Wiesberger. “I didn't hit as many fairways as I would have liked to, but the rough is not up much, so the closer you get to the green, the more shorter clubs you can hit.
“It's not playing particularly long today, so a lot of wedges in and more chances to make more birdies.”
Gallacher has gone two days without a bogey as he seeks only his second title in almost 400 European Tour events - but there was only one birdie in his second round 70.
“I hit greens in regulation, so I had pretty much 35 putts,” said the 37 year old. “Some were close, some were good two putts from distance; so it was about even really.”
Of Europe’s three Ryder Cup heroes present only Francesco Molinari will be around for the weekend action.
The Italian shot a second straight 71 to make the cut on level par, but Martin Kaymer’s 75 saw him miss out on two over and Captain José María Olazábal shot a 75 for eight over.