West Ham captain Mark Noble converted a penalty just before half-time following a handball from Cristian Sapunaru but the Hammers were pegged back on 83 minutes by Denis Alibec.

Slaven Bilic's team will hope to avoid a second successive exit at the hands of Astra in next Thursday's return leg at the London Stadium, having lost to the Romanian side in last year's third qualifying round.

Shakhtar Donetsk, the 2009 UEFA Cup champions, earned a 2-1 advantage after beating Istanbul Basaksehir in Turkey, while Anderlecht, Fenerbahce and Olympiakos secured first-leg victories.