not the quickest when United are at Home,
Best bet is to go to Shudehill Bus station and get either M10, 10, 67, 68 or 100, M10 and 10 avoid United routes, good pub facing the Bus station as well Hare and Hounds,
Best way to Shudhill is walk down from Piccadilly through Piccadilly gardens towards Debenhams and follow the tram tracks alongside the Arndale.

Please note that the Metrolink is not currently operating from Piccadilly, due to engineering work in Manchester City Centre. Nearest station on the Eccles line (that will get you to Weaste) is St. Peters Square.[url=http://www.metrolink.co.uk/servicedisruptions/details.asp?id=218<<Link>>[/url

Having said that, what time are you planning on getting to The Willows by? Kick-off for the Solly game is at 1800. If you get either the 1714 or 1726 tram from St. Peters Square, the United fans should already be at Old Trafford by then, kick-off for their game v Spurs is 1730. Journey time from St. Peters Square to Weaste is 20 minutes, so the 1714 or 1726 will do you.

Alternatively, another round-about way you could get to Weaste from the City Centre, completely avoiding Old Trafford, would be to get a train from Manchester Victoria to Eccles (they run at xx39 every hour on a Saturday afternoon, journey time is 7 minutes), and then get the tram (for two stops) back from Eccles to Weaste.

thanks for that,i get into piccadilly at 4,so the Shudehill buses or victoria train look the best options.

Get a taxi.

a taxi would be about £10