The midfielder magically weaved his way through the Bayern defence and produced a low finish that went in off the post to put the home side in front after 11 minutes.

Diego's Simeone's superbly-drilled outfit then snuffed out Bayern's threat and even came close to doubling their lead late on when Fernando Torres's shot struck the post.

"It was a great game, everyone believed in their work. We put in a huge effort," said Simeone, whose Atletico side have frequently been a scourge of more-fancied opponents with their disciplined rearguard frustrating Barcelona in the last round.

While Bayern’s David Alaba also hit the woodwork with a thumping drive, the result left Pep Guardiola’s side facing a huge task in next week's return leg in Munich to avoid a third successive semi-final exit.

"I’m not happy with how we played," said Guardiola, who is leaving Bayern in the close-season to join Manchester City.

"We started badly. The goal was a consequence of our slow play. We didn't win even one battle."

Atletico made an intense start in the first competitive meeting between the two sides since Bayern beat the Spaniards 4-0 in the 1974 European Cup final replay.

Saul drove them in front with a sensational run from the right, snaking inside and beating three players before fending off two more and bending the ball in off the far post with a flick of his left boot.

Bayern nearly equalised moments later when Arturo Vidal’s looping header beat Atletico keeper Jan Oblak, but Jose Gimenez rose to head the ball off the line.

Simeone’s side might have added another before the break when Antoine Griezmann bore down on goal before the Frenchman’s near-post shot was kicked away by Bayern keeper Manuel Neuer.

Bayern were more incisive in the second half. Alaba smashed the underside of the crossbar from 30 metres, and then Javi Martinez escaped his marker at a corner but could only glance the ball into the hands of Oblak.

Atletico soon regained control, leaving Bayern to try their luck from distance. Douglas Costa blasted over from 30 metres, and Vidal tried to surprise Oblak from range, but the Slovenian got across in time to parry.

Atletico almost doubled their lead with their only real chance of the second half.

Torres stormed into the box, took on a defender and tried to hook the ball into the far corner, hitting the post before Koke’s effort on the rebound was caught by Neuer.

The winners of the tie will face either Real Madrid or Manchester City in the final on May 28.