Austria closed in on a place at Euro 2020 when a first-half goal from defender Stefan Posch gave them a crucial 1-0 win away to toothless Slovenia, who suffered their second defeat in four days on Sunday.
Austria, with 16 points from eight games, are second in Group G and five points clear of North Macedonia and Slovenia with two games to play. The top two in the group qualify directly for next year's European Championship.
The game was won by the simplest of goals in the 21st minute as Austria took a corner on the left and Posch scored with a glancing header at the near post after getting in front of the defenders, the 22-year-old's first goal for his country.
Oblak was called into action again to make a one-handed save from Marcel Sabitzer's 20-metre effort.
Slovenia's frustration boiled over in the 88th minute when substitute Denis Popovic, who had only been on the field for 10 minutes, responded to a challenge from Sabitzer by elbowing the Austria forward in the cheek and was shown a red card.
Slovenia, beaten 2-1 by North Macedonia on Thursday, managed only two shots on target.
Austria lost their first two games in the group but their subsequent six games have produced five wins and a draw.