Marouane Fellaini is hurting as much as anyone after the Manchester derby defeat, but knows United cannot afford to dwell on it with domestic and European assignments to balance.

Jose Mourinho saw his 100 per cent start to life at Old Trafford come to an end on Saturday when Pep Guardiola's Manchester City emerged 2-1 victors from a pulsating clash.

Fellaini was disappointed by the loss and has bizarrely admitted United lacked aggression in what was the biggest game of the season so far. United cannot allow that feeling to fester, with the Red Devils having to prepare for Thursday's trip to Rotterdam to take on Feyenoord in their Europa League opener.

Marouane Fellaini has admitted Manchester United lacked aggression against rivals City

Fellaini wants United to put their 2-1 defeat behind them ahead of a busy run of fixtures

'The problem was we needed to be more aggressive to win the first and second balls but we didn't. However, the attitude was better in the second half,' Fellaini said.

UNITED'S NEXT FIVE GAMES September 15: Feyenoord (away - Europa League) September 18: Watford (away) September 21: Northampton (away - EFL Cup) September 24: Leicester (home) September 29: Zorya Luhansk (home - Europa League) Advertisement

'We didn't have the aggression in the first half, but that doesn't matter now. We have to focus on the next game and we have to win.'

He added: 'Everyone is disappointed, which is normal after losing a derby, but this is the fourth game of the season and every team will lose games,' the Belgium midfielder said.

'We have to focus on the next game now and be ready.

'The first half was difficult, but we created chances as well and it could have been 2-2 at the end of the half, so I think that is not the problem.'

The Belgian finds himself on the floor as John Stones and Nicolas Otamendi win the ball

Jose Mourinho was left frustrated as his United side lost their 100 per cent league record

The clash with City was the first of six September matches, with a Premier League trip to Watford and EFL Cup clash at Northampton following their journey to Holland.

Reigning champions Leicester and then Ukraine's Zorya Luhansk arrive at Old Trafford during a frantic month that offers United the chance to build up some positive momentum after their derby loss.

'We were always in Manchester City's box causing trouble,' Fellaini told MUTV.

'But we did not hit the target enough so it is always going to be difficult to score. We have 34 more games, so we must win our next game.

'We have to recover quickly because we have a game on Thursday and Sunday.