In the end the outcome was thoroughly predictable as Manchester United strolled into the FA Cup quarter-finals and Louis van Gaal cherished the breathing space and respite that a routine victory provided. There were no expletive-laden chants from the travelling fans or calamitous defensive errors on the pitch on this occasion as United emphasised the chasm between two clubs separated by 60 places on the league ladder and a million miles apart in many other respects. For Shrewsbury, who are fourth from bottom in League One, it was a chastening night at times as they spent long periods of the game chasing shadows against a United side that never gave their opponents the slightest encouragement to believe that there could be an upset on the cards. It was not a victory to repair the damage inflicted during that dismal 2-1 Europa League defeat against Midtjylland – the only way that will happen is if United overturn the deficit at Old Trafford on Thursday night – but this was a professional performance from Van Gaal’s players and a positive result to lift the mood if nothing else. United, in truth, were coasting and there were moments when it felt like a…