Five things we learned from the weekend fixtures, including Chelsea’s Diego Costa and Arsenal’s central midfield frustrations

Manchester United still need huge work

They got their first point of the season at Sunderland, but Louis van Gaal’s Manchester United toiled once again and were perhaps lucky not to lose on Wearside. Attacking trio Wayne Rooney, Robin van Persie and Juan Mata are clearly dangerous, but were starved of service by the limp and one-paced midfield behind them, whilst their defence also looked constantly on the verge of collapse. Angel di Maria would be a start, but little more than that.