Manchester United ought to have been aware of Xherdan Shaqiri's potential to decide football matches.
On his Liverpool debut in pre-season, the Swiss playmaker announced himself with a marvellous bicycle kick in a 4-1 victory over Jose Mourinho's team in Ann Arbor.
In retrospect, it was clear from that evening in the United States that these were two teams heading firmly in opposing directions. The possession stats - 65 per cent to Liverpool, 35 per cent to United - were identical to Sunday's procession at Anfield and Shaqiri had a pivotal influence in both matches.