Kenyan Olympic champion Sammy Wanjiru survived the scorching early pace to take an ultimately winning lead and break the course record in the men's London marathon on Sunday.

Wanjiru clocked two hours five minutes 10 seconds to better compatriot Martin Lel's course record by five seconds. Defending champion Lel, who was aiming for a record fourth London win, withdrew on Saturday because of a hip strain.

Germany's Irina Mikitenko retained the women's title after repelling a spirited challenge from Britain's Mara Yamauchi.

A trio of pacemakers took the men's field through the halfway point on a sunny spring morning in 61 minutes 35 seconds, the fastest ever split in a marathon.

Inevitably the pace slowed as the field emerged from London's docklands. Wanjiru made his move at 29 km and surged twice to take the lead over the other two Beijing medallists, Tsegaye Kebede of Ethiopia and Moroccan Jaouad Gharib.

He appeared to have a comfortable margin at the front of the field before Kebede, the Beijing bronze medallist, began his victory bid move over the final kilometres.

Wanjiru glanced apprehensively over his shoulder several times before summoning his resources for a final time to head Kebede by 10 seconds. Twice world champion Gharib was third seven seconds further back.

"It was a very tough finish," Wanjiru told reporters. "Over the final 200 metres I felt I could win. To get the course record is fabulous but all I wanted to do was win."

Kebede added: "At 40 kilometres I felt a pain in my side but I felt I had to keep on."

THREE-WAY BATTLE

Eritrean Zersenay Tadese, whose marathon debut had excited much interest after a distinguished track and cross country career, dropped out after 35 km.

The women's race quickly turned into a three-way tussle between Mikitenko, Chinese Olympic bronze medallist Zhou Chunxiu and Yamauchi.

Zhou found the pace too hot after 27 km and Mikitenko seized her opportunity to put the pressure on Japan-based Yamauchi, breaking away at 32 km and steadily increasing her lead.

Mikitenko finished in 2:22:11 to record her third win in only four marathons with Yamauchi, who finished sixth in Beijing, clocking a personal best 2:23:12. Russian Lilya Shobukhova came through strongly in the latter stages to finish third in 2:24:24.

"I was feeling confident that I had it my legs," Mikitenko said.

Yamauchi provided ample consolation to the large crowds packing the streets of London for the absence of British world record holder Paula Radcliffe, who pulled out of the race because of a broken toe.

"I have made a big improvement in the last two years," she said. "So I just wanted to give everything. The crowds were fantastic."

Olympic champion Constantina Dita of Romania dropped out at the halfway stage complaining of breathing difficulties.