NORTH Ballarat is a new joint Victorian Football League premiership favourite.The Roosters made the biggest statement to date in their premiership defence with a two-point victory over the previously unbeaten Williamstown at Williamstown yesterday.Williamstown had been unchallenged in its opening six assignments for the season, but met its match in a disciplined North Ballarat, 14.16 (100) to 15.8 (98).North Ballarat coach Gerard FitzGerald said the win indicated how far the Roosters had come since the start of the season _ when thrashed by Williamstown in a practice match and then brushed aside by Port Melbourne in the opening round.The Roosters have gone on to win six straight."We learnt from those and you were fantastic today," he told his players."Our discipline was first class."That's what wins tight games."FitzGerald said Williamstown had clearly been up to now the best team in the competition."Now we have to keep getting better," he said.Williamstown's superior percentage keeps it on top of the ladder, but North Ballarat has the same record with six wins and one loss.With Northern Bullants losing to Collingwood and dropping three places to fifth, the Roosters have climbed from third to second.