A 4-0 victory in Ukraine has given Bayer 04 Leverkusen a commanding lead in their UEFA Europa League round of 32 tie with FC Metalist Kharkiv.
The Group B winners continued their impressive form in the competition with Eren Derdiyok and Gonzalo Castro scoring in either half at the Metalist Stadion. Sidney Sam then added two further strikes in second-half added time to make the German side clear favourites to progress.
The hosts made an energetic start with Jonathan Cristaldo firing an early effort across goal. However, Leverkusen settled swiftly and soon struck as Renato Augusto exchanged passes with Derdiyok before slipping in Hanno Balitsch on the left, the midfielder's low cross tucked away at the far post by Derdiyok.
Taison thumped the upright from a narrow angle as Metalist attempted to rediscover their early promise but the visitors now carried the greater threat, Renato Augusto testing Vladimir Dišljenković from 25 metres.
The half-time interval failed to becalm Leverkusen, who were unbeaten in all eight of their matches in the competition before their trip to Kharkiv, but Metalist did create two chances. Cristian Villagra's drive from 30 metres was saved by René Adler while Serhiy Valyayev was denied by a last-ditch tackle from Domagoj Vida.
Leverkusen showed greater poise on the counterattack, however, and extended their lead on 72 minutes. Renato Augusto was integral again, finding Derdiyok and latching on to the return pass to dart in on goal. The Brazilian clipped his shot over Dišljenković and although Cleiton Xavier denied him on the line, his clearance rebounded off substitute Castro into the net.
Derdiyok and replacement Simon Rolfes then spurned presentable chances but Sam was less profligate, rounding Dišljenković for number three before his deflected effort all but condemned Metalist ahead of the return in Germany on 24 February.