Brazilian striker Marlos struck a first-half double as Shakhtar Donetsk strolled to 3-0 victory over Monaco in the heat of Lublin.
In soaring temperatures in Poland it was the Ukrainian side who coped better, Marlos netting twice in the opening 45 minutes before compatriot Taison added a third after the break.
Marlos opened the scoring early with a low shot across Seydou Sy in the Monaco goal and doubled the advantage before half-time despite offside calls from the Ligue 1 side.
The 27-year-old went close to grabbing a hat-trick, before Corentin Tirard had Monaco's best opening, Andriy Pyatov denying the youngster after a one-two with Anthony Martial.
Any momentum Monaco had quickly disappeared in the second half as Taison completed Shakhtar's win with a deflected free-kick, the forward's effort leaving substitute goalkeeper Paul Nardi stranded.
