Fernando Llorente scored two second-half penalties as Athletico Bilbao fought back from two goals down to avoid a Europa League upset against Salzburg on Thursday night.
The Spaniard's unbeaten start to Group F looked to be coming to an end when Wallner and Leonardo put the visitors in control before half-time.
But Spain striker Llorente rescued a point for his side by blasting home two unstoppable penalties in quick succession and keep Athletic firmly on course to reach the knockout stage.
The Austrians finished the game with 10 men as Rasmus Lindgren was sent off for the handball which gave away the second spot-kick.
The win moved Athletic on to seven points at the top of the pool, three points ahead of Salzburg and Paris St Germain.
Wallner served notice of his intentions in the 28th minute by firing in a shot from 18 yards which goalkeeper Gorka Iraizoz tipped round the post.
But the much-travelled forward was celebrating two minutes later when he took a pass from Leonardo and picked out the bottom right corner from inside the area.
Llorente headed wide from close range before Wallner and Leonardo again combined to double the Austrians' lead.
This time Wallner was the provider, playing the ball in from the left for the Brazilian to guide a low shot into the far left corner from the right edge of the area in the 36th minute.
The Spaniards were stunned, but almost got one back through Llorente a minute later only for Eddie Gustafsson to turn his header round the post.
Salzburg were happy to hold onto what they had and Gustafsson was booked for time wasting with more than half-an-hour to go.
But the hosts grabbed a lifeline in the 67th minute when Ibrahim Sekagya fouled Ander Herrera and Llorente crashed the resulting penalty high into the net.
And the visitors shot themselves in the foot again seven minutes later.
Lindgren handled the ball in the area and, after he had been sent off for a second booking, Llorente hammered home the equaliser from the spot.
From then on there was only one winner, but Athletic were frustrated in their search for a third to complete the comeback.