GLASGOW, Sept 15 (Reuters) - Champions Celtic knocked rivals Rangers off the top of the Scottish Premier League (SPL) with an emphatic 5-0 win over Inverness Caledonian Thistle, helped by a double from Jan Vennegoor of Hesselink, on Saturday. Celtic took the lead through Vennegoor of Hesselink in 15 minutes when he used his knee to divert a ball from Scott Brown into the bottom left-hand corner of the net. Just before the break Italian midfielder Massimo Donati fired in a second goal which took a deflection. Japanese midfielder Shunsuke Nakamura crashed a magnificent 25-metre shot into the top left-hand corner of the net for 3-0 in 56 minutes before Vennegoor of Hesselink headed the fourth. Scott McDonald whipped in a low shot which was deflected past his own keeper by Phil McGuire for number five after 71 minutes. Rangers crashed to their first SPL defeat of the season earlier on Saturday as Hearts claimed their first league win with an exciting 4-2 victory at Tynecastle. Rangers manager Walter Smith said: 'No aspect of our game was decent. The first 20 minutes, I didn't think we handled the game very well and they put us under a bit of pressure. So we are disappointed from that point of view.' Rangers striker Kris Boyd went off with a bad head cut, putting him in doubt for the side's Champions League clash with Vfb Stuttgart on Wednesday but Smith said there was still a chance he could play. Hibernian drew 1-1 at Falkirk while Aberdeen lost 2-1 at home to Motherwell and Gretna slumped to a 2-1 defeat against Kilmarnock.