Australian wildcard Alex De Minaur will face Milos Raonic in the second round of the Brisbane International after claiming a surprise win over Steve Johnson on New Year's Eve.

The 208-ranked De Minaur defeated the American 7-6 (9-7) 6-4 on Pat Rafter Arena to set up a meeting with world number three and 2016 champion Raonic.

De Minaur, 164 places below Johnson in the rankings, saved two set points to force a tie-break and another three before taking the opener with his first opportunity.

The 18-year-old was a break down at 4-3 in the second set, but was back on serve immediately and wrapped up the victory with a second break courtesy of a backhand winner down the line to end 2017 in promising fashion.

"I'm pretty delighted; it's the best way to finish off the year," said the Sydney-born outsider.

"I played a great match and beat a high-quality opponent, I'm stoked. I showed how I can play today, so now it's all about maintaining that level."

Sixth seed Diego Schwartzman was knocked out on day one of the tournament, losing 6-4 7-6 (7-3) to Alexandr Dolgopolov.