NAIROBI, April 11 (Xinhua) -- Kenya's Olympiad Mary Keitany will be chasing history in her defense of the London Marathon on April 22.

However, the New York marathon silver medallist feels no pressure to shatter the 15-year-long world record by Paula Radcliffe of two hours, 15 minutes and 25 seconds.

IAAF, the athletics' world governing body, recognizes two world records - mixed-gender and women only - and last year Keitany broke Radcliffe's 'women-only' world best in a time of 2:17:01.

Keitany will run with male pacemakers and expects the weather and the form to help her race to a world record.

"Male pacemakers will give me a new edge. Form is temporary and I feel I am at my best. Hopefully I will be able to attain my target," she said.

Keitany, who is the defending champion of the London marathon, says alongside having the weather perfect, she is looking out to the support of the people of London.

"Everything needs to be in order. When you talk of similarities, everyone focuses on what they can do. But you must be motivated to do your event and achieve what you want," she said.

Among Keitany's main challengers in London will be Chicago marathon champion Tirunesh Dibaba of Ethiopia.

"I saw her run in Chicago and she was running really good. It was a fantastic race for her and we are like neighbors, Kenya and Ethiopia and we meet in various races and we are used to each other," said Keitany.

But Dibaba has warned she is up to the task and will not be happy with second spot.

"I'm going to be well prepared to win the race," Dibaba told London marathon organizers.

"Last year Keitany was really good and she had her own strategy and she won. But I am now ready for any eventuality," she said.

Alongside the victory and world record in London, Keitany will follow the proceedings in Boston Marathon on Monday with keen interest as she seeks to know her fate in the quest for the World Marathon Majors.

American Shalane Flanagan can stake a strong claim with a second win of the series in Boston marathon but Keitany and Dibaba will have something to say about that in London Marathon.