GLASGOW, Aug 12 (Reuters) - Champions Celtic beat promoted St Mirren 2-0 in the Scottish Premier League on Saturday with a goal in each half.
Captain Stephen McManus headed the opener in the 28th minute and Bulgarian midfielder Stilian Petrov grabbed the second to secure the points.
The victory put Celtic on six points from three games but they were soon overtaken by Hearts and Falkirk who played out a 0-0 draw.
They both have seven points but Hearts are top on goal difference. St Mirren, who had won their first two matches, slip to fourth.
Celtic manager Gordon Strachan told BBC Radio Scotland: 'I was happy with some of the football but after going 1-0 up we lost our shape in terms of attack that we needed to rectify.
'So, there are little things to work on and we will get that right.'
Hearts goalkeeper Craig Gordon blamed his team's lacklustre show on tiredness following their 2-1 Champions League third round qualifier defeat in midweek by AEK Athens.
'We played for half an hour with 10 men on Wednesday (after a man was sent off) and it took it out of the legs,' he said.
Elsewhere, Aberdeen won 2-0 at Motherwell with a double from Darren Mackie and Kilmarnock drew 0-0 at home to 10-man Dundee United who had Lee Miller sent off. Inverness Caledonian Thistle also drew 0-0, at home to Hibernian.
Rangers, who have four points from two games. are away to Dunfermline Athletic on Sunday.