The Belgian side, whose own play-off hopes took a hit, claimed a surprise lead before Roberto De Zerbi's team turned things around.

Anan Khalaili opened the scoring just five minutes in with a lovely low drive after cutting inside from the right to pick out the bottom-right corner.

However, Marseille struck back just 10 minutes later when Igor Paixao latched onto the rebound of Pierre-Emerick Aubameyang's saved shot and fired into the roof of the net.

Greenwood got the first of his double four minutes before the break, drilling his low effort past Kjell Scherpen, who got a hand to the ball but could not stop it from hitting the net.

In the 58th minute, Greenwood seemingly put the game out of sight for Marseille. He raced in behind before turning his defender and bending a lovely strike into the bottom-left corner.

However, Union SG refused to back down, with Khalaili getting his second of the game after latching onto a loose clearance, but their fight fizzled out.

Kevin Mac Allister and Promise David both had late goals ruled out for offside, before Geronimo Rulli made a stunning save in the closing seconds to keep out the latter's header.

Elsewhere, Monaco moved to 18th in the table after edging to a 1-0 win over Galatasaray thanks to Folrain Balogun's 68th-minute goal.