Basel beat Sheriff 1-0 but missed a 90th-minute penalty in the first leg of their Champions League playoff tie on Wednesday.
Valentin Stocker scored in the 54th with a close-range header from teenager Xherdan Shaqiri's cross.
The Swiss champion was denied a second goal when Sheriff goalkeeper Vladislav Stoyanov saved Benjamin Huggel's spot kick.
Sheriff came closest to scoring when Alexandr Erokhin's shot in the 73rd struck the underside of the crossbar. Erokhin was sent off for receiving a second yellow card in the 86th.
Moldova's champion is trying to reach the group stage for the first time in 10 straight years of Champions League play. The return is in Tiraspol next Tuesday.
Sheriff came to defend and let its hosts dominate first-half possession.
Basel threatened when left-back Behrang Safari advanced, and the Sweden international's cross in the 11th minute was struck into the net by Alex Frei from an offside position.
Neither side delivered a shot on target until Frei's free-kick in stoppage time was pushed away by Stoyanov diving low to his right.
Sheriff showed more intent in the second half and Florent Rouamba's 20-meter (yard) shot was grabbed with both hands by goalkeeper Franco Costanzo.
In the 51st, Huggel rose to head a corner against the outside of Stoyanov's right-hand post.
Three minutes later, Huggel's height disrupted the visitors' defense and the ball fell to Shaqiri on the right for a clever cross that set up Stocker at the far post.
Frei's header was too high in the 57th, then his fierce volley from Safari's pass in the 75th brought a diving, one-handed save from Stoyanov.
Sheriff substitute Marko Djurovic went close with a 68th-minute header, then Erokhin saw his shot from eight meters (yards) rebound off the bar.
The Russian forward was booked a minute later, then dismissed after petulantly throwing the ball to the ground to protest a decision by Norwegian referee Terje Hauge.
Basel got its chance for a valuable second goal when Stoyanov brought down Federico Almerares as the substitute tried to round him.
The 23-year-old Bulgarian escaped without even a yellow card then dived low to his left to push away Huggel's penalty.
