I think you will be pretty worried if you're 6 points behind United come Sunday evening.
It's 1st v 2nd and is the biggest fixture for the fans every season in the league.
Not massively I wouldnt no, we still have to play Utd again yet after that, so even if we ended up 6pts behind them on sunday evening, win the 2nd meeting against them and its a 3pt gap which would just mean needing to win 1 other match that Utd lose to be level again. The single result on sunday really doesnt worry me, as disappointing as that might be to Utd fans to hear, but the run after sunday against Spurs, Man City, Leicester and Everton..thats much more worrying to me because its far harder to close a gap caused by a run of point drops than it is to close a gap caused by a single match point drop.