Mr Barclay (24) was celebrating last night at the Heartland Hotel in Gore with about 150 supporters, family members and friends who watched as National made a stronger showing in the polls than some expected.
"It's great, it's been great: we've been extremely proud of how National is going and we hope we can deliver a final result that can see National govern with a strong majority," Mr Barclay said about 9.45pm.
Mr Barclay held a majority of 13,583 over Labour's Dr Liz Craig last night.
He said the win had yet to sink in, and believed the work of ex-Clutha Southland MP Bill English had helped pave the way to his success.
"His presence and work in the electorate has made my coming in a lot easier," he said.
With only 3,323 special votes being recorded in the electorate it looked like his total would fall short of Mr English's 21,375 tally in 2011, but Mr Barclay said he "certainly wasn't expecting to deliver a result that high".
"I think it would have been an insult to the work he's done had I done that."
Mr Barclay had yet to make a connection with the man who formerly held his seat.
"I've been trying to set up Skype for the last half hour," he said. "It'd be nice to do that."
Mr Barclay said after meeting people in the electorate during meet the candidates nights he realised the mood among voters was for another three years with National.
"People have realised we have come along way as a country and the economy has come a long way as well," he said.
"People have realised the hard times we have gone through and they have realised the opportunities ahead."
