The hosts were unbeaten in their previous four Europa League round of 16 first legs and looked set to extend that run after 17 minutes, going ahead when Francisco Trincao threaded the ball through to Paulinho, who was afforded too much space down the left flank and fired the ball across Juan Musso and into the net.
Having barely threatened, Atalanta were millimetres away from an equaliser twice in the 24th minute. First, Emil Holm marauded into the penalty area and his cross-cum-shot deflected off Ousmane Diomande and struck the inside of the post before La Dea worked the ball forward to Gianluca Scamacca, who set himself from 25 yards out and hit the outside of the same upright.
Home goalkeeper Franco Israel denied further chances before Atalanta grabbed a deserved equaliser in the 39th minute.
Israel sprinted out of his area to beat Ademola Lookman to a loose ball, but could only clear it to Aleksei Miranchuk. The Russian fed Scamacca, who kept his composure to hold off the Sporting defence and finish past the scrambling Israel.
The same players almost combined for a second Atalanta goal before the break, but an Israel fingertip save denied Scamacca’s header from Miranchuk’s corner.
Ruben Amorim made three changes at half time in an attempt to weather the storm, which initially proved successful, although it was one of his starters, Geny Catamo, who had the first effort of the second half when he forced a save from Musso.
However, Atalanta showed how dangerous they still were on the hour mark, as Lookman danced through the defence and became the third Atalanta player to strike the post, with Israel beaten.
Approaching the final 15 minutes, visiting players were queueing up to finish off a free-kick routine, but Sead Kolasinac sent his header wide. El Bilal Toure had the ball in the hosts’ net with five minutes to go, but his strike was ruled out for offside.
Having come through Group D, the two sides will meet for the fourth time in the competition next Thursday, as Atalanta look to maintain this season’s unbeaten Europa League record, while Sporting will aim for just a sixth win over Italian sides in what will be their 35th such fixture.
Flashscore Man of the Match: Gianluca Scamacca (Atalanta)
