Manchester United have suffered a massive injury blow with Belgium manager Roberto Martinez confirming that Marouane Fellaini may have suffered knee ligament damage which would mean a lengthy spell on the sidelines. The midfielder was struggling to move before signalling to the bench at the 29th minute with his side 1-0 up.

Fellaini sat out of training with his national team this week, owing to an Achilles injury picked up following a nasty challenge from Southampton's Shane Long on 23 September. However, he was back starting in their World Cup qualifier against Bosnia and Herzegovina, but failed to finish the game owing to the injury.

A major injury to Fellaini will come as a big setback to Jose Mourinho, especially with the midfielder emerging as a key player this season in the absence of Paul Pogba, who suffered a hamstring injury in the first Champions League fixture of the season and is sidelined since then. The midfielder is all but ruled out for their game against Liverpool next weekend as they face their first test from last season's top six.

After the game, Martinez said, as quoted by Sky Sports. "We are all worried about Fellaini. We fear that there's ligament damage." A Belgian FA official also confirmed the injury, and said: "It is something to be worried about on first sight. Ligaments, left knee. More news tomorrow."

Michael Carrick has also been unavailable through injury, with Nemanja Matic, who has played every minute of the Premier League campaign so far, and Ander Herrera Mourinho's only other options. Mourinho confirmed that Pogba is a "long-term" absentee with the injury worse than first feared, but the Frenchman has shown considerable progress by stepping up his recovery process.

Meanwhile, Romelu Lukaku missed training on Monday (2 October) and underwent a scan which revealed that there was no major damage. But the United forward continued to train away from the rest of the squad and was left out of the team against Bosnia.

Marouane Fellaini managed just 29 minutes before he was forced off in Saturday's qualifier against Bosnia. Getty