"The condition of the weather was very fine and my body was fine, but the pacemaker was going too slowly. He said he was tired," the 22-year-old Kenyan said. "I think they should get a good pacemaker from the starting point to 35K.
"But I got good experience and maybe next time if we can get a good pacemaker, I can set a world record."
Wanjiru used a series of surges to hold off Kebede, who finished the 26.2-mile race 10 seconds behind in a personal-best time of 2:05:20. Gharib was third in 2:05:27.
"Around 42K, I felt that I had to keep running as hard and as fast as I could because I wanted to win," Kebede said. "There were some very good runners here and to beat them is a good feeling."
Martin Lel, who'd won three of the last four London marathons and set a course record last year, pulled out of the race Saturday because of a hip injury.
In the women's race, the 36-year-old Mikitenko broke away from the field to win in 2:22.11.
In the final 6 miles, the German runner surged ahead of Mara Yamauchi of Britain, who finished 1:01 behind. Liliya Shobukhova was third in 2:24:24, one of four Russians in the top 10.
"I was always confident that I had it in my legs as everything in myself felt good, and after 19 miles I saw no reason why I shouldn't win," Mikitenko said. "From a physical point of view it felt a tougher race this year than last, but I when I got away I always felt strong.
"I've won in Berlin and London again. If I can run like this for the next couple of years I will be happy."
The Japan-based Yamauchi ran a personal-best 2:23:12.
Olympic champion Constantina Dita of Romania slipped off the pace and pulled out after the halfway mark with breathing difficulties. Beijing Games silver medalist Catherine Ndereba was seventh, and bronze medalist Zhou Chunxiu, the 2007 London champion, finished 12th.
Britain's Paula Radcliffe, the world record-holder and a three-time winner, pulled out last month because of a broken toe.
Australia's Kurt Fearnley won the men's wheelchair event and Amanda McGrory of Kennet Square, Pa., won the women's race.
Wanjiru and Mikitenko extended their leads in the Marathon Majors series with their victories. Wanjiru leads Boston Marathon winner Deriba Merga by 35 points, while Mikitenko leads Boston runner-up Dire Tune by 35 points as well.
