Liam Buchanan scored twice as struggling Livingston claimed an impressive 4-1 win at relegation rivals St Mirren.The visitors claimed a first win in the Ladbrokes Championship since late October, with Ben Gordon and Gary Glen also on target. Lawrence Shankland scored for St Mirren.Buchanan put Livi ahead in the 23rd minute and Gordon added the second nine minutes later.Shankland gave the hosts hope by pulling one back four minutes before the break, but that was dashed when Glen fired home Livingston's third nine minutes after the restart.And the visitors put the seal on a thumping win, which moved them above their opponents on goal difference, when Buchanan grabbed his second in the 66th minute.