ADELAIDE (AFP) - Germany's Andre Greipel blitzed his rivals to win the fourth stage of the Tour Down Under on Friday, as Cadel Evans saw his overall lead slip to just seven seconds.

Greipel had too much speed for the rest of the field on the final sprint into Victor Harbour to win by over two bike lengths.

The stage win was his 15th at the season-opening UCI World Tour event, but his first this year.

The German said the 2014 race course had not suited the sprinters, so he had to take his chances when he could.

"I think this was actually the first opportunity for sprinters today," he said.

Greipel's Lotto-Belisol teammate, Jurgen Roelandts, finished second ahead of Italian Elia Viviani (Cannondale), with Simon Gerrans (Orica GreenEdge) coming in fourth.

Former Tour de France winner Evans finished in the leading group of 50 riders to retain the ochre leader's jersey, although fellow Australian Gerrans closed the gap to seven seconds after picking up time bonuses on the two intermediate sprints.

The 148.5km stage from Unley in inner-city Adelaide to the seaside town of Victor Harbour was comparatively flat and tailor-made for the sprinters.

A group of five riders broke clear early, but when they began to slow Frenchman Axel Domont (FDJ) and Australia's Cameron Wurf (Cannondale) launched an attack, at one stage getting over four and half minutes clear.

However, in a familiar pattern at the Tour Down Under, the main peloton began to pick up the pace on the approach to the King of the Mountain climb at Myponga, and soon after they passed the summit the leaders were reeled in.

The course then took the riders along a ridge top and, with strong cross winds causing havoc, Orica GreenEdge made a decisive move which split the peloton in two for the last 25 km.

Greipel's Lotto-Belisol team reacted superbly to the move, with six of their seven riders in the front group.

However, his main sprint rival, fellow German Marcel Kittel, missed out and was left languishing in the second group 13 minutes behind the leaders.

Omega Pharma-QuickStep pair Jan Bakelants and Serge Pauwels attacked with 4km to go and had some hope of staying away but they were caught inside the last kilometre, leaving the race open for the sprinters.

Greipel's teammates led him out superbly and once the big German began to accelerate there was no stopping him.

"I think we (Lotto-Belisol) finished first and second which says enough - it was a real team effort today," he said.

"We survived the attack by GreenEdge in the cross-wind with six guys so we could put the pressure on.

"It makes me really happy that we finally got the win."

Friday's 151.5km stage from McLaren Vale to Willunga includes two climbs up Willunga Hill and should suit Evans more than his rival Gerrans.