Andy Williams struck twice as in-form Swindon underlined their automatic promotion credentials with a 3-0 win at 10-man Notts County.The Robins were too quick and too clever for the Magpies as Mark Cooper's side sent out an ominous message to their rivals.They took the lead after just six minutes when Massimo Luongo released Williams who slipped a shot beyond Roy Carroll and into the far corner of the net.Notts boss Shaun Derry introduced Michael Petrasso at half-time to try to inspire the hosts, but it was the visitors who took control of the game.Williams lashed in his second goal of the afternoon in the 54th minute when he converted an excellent cross from Ben Gladwin at the far post.Liam Noble was then sent off for a challenge on Nathan Thompson to leave the Magpies with a mountain to climb.And Cooper's side made the extra man count in the 59th minute when Luongo, who was excellent throughout, rammed home a shot from Gladwin's pull back to seal a fifth successive league win for the Robins, who stay second in the table.