US presidential hopeful Mitt Romney has clinched a four point poll lead on Barack Obama after his barnstorming performance in last Wednesday’s debate, according to the Pew Research Center. The latest national poll, carried out from 4-7 October , gave Romney and Obama both 46 per cent support among surveyed registered voters, while among likely voters Romney leads by 49 per cent to 45 per cent. Nearly two-thirds of those surveyed by Pew thought the Republican candidate did a better job in last week’s debate. Romney trailed by nine points (42 per cent versus 51 per cent) last month. The election takes place on 6 November.