Sasa Kalajdzic scored his first league phase goal of the Champions League
LASK picked up their first Champions League victory with a brilliant comeback win that ended Sporting's perfect start.
The hosts, who won their opening two games, took a fifth-minute lead through Luis Suarez's penalty after Scottish referee Nick Walsh adjudged that Nestory Irankunda had been tripped.
However, LASK equalised 10 minutes later through a superb Christoph Lang finish. He was found on the edge of the area, took a touch and then drilled across the goalkeeper and into the far corner.
The rest of the first half was pretty even, but the visitors, who had lost their past eight away games in major European competition, were clinical in the second half.
Sasa Kalajdzic gave them the lead in the 63rd minute when he was found on the right during a counter-attack and he picked out the far corner with a precise finish.
The Austrian champions extended their lead on the break, with Krystof Danek forcing home via the near post.
Sporting gave themselves late hope through Suarez, but LASK held on for their first-ever away win in Europe's top competition.
Sporting visit Shakhtar Donetsk, who are playing at Chelsea's Stamford Bridge, in their next match on 3 November, while LASK host Slovan Bratislava on the same evening.
Watch highlights of every Champions League game from 22:00 on Wednesday on BBC iPlayer and the BBC Sport website and app.
There will also be a Champions League Match of the Day on BBC One on Wednesday, from 22:40 to 00:00.
