NAIROBI, Jan. 25 (Xinhua) -- Olympic Champion Vivian Cheruiyot is not fretting on the caliber of opposition that threaten to beat her at the London Marathon on April 28.

The 35-year-old, who will be making her fifth race since turning to marathon two years ago, says the trick is in her training.

"I train well so I know I can afford to relax and time my own run to perfection. I don't need to go with the group, but keep my discipline and attack when required," she said Friday in Nairobi.

Cheruiyot, an inspector in Kenya's police force, will compete with fellow Kenyans Gladys Cherono, winner of Boston Marathon, Chicago Marathon champion Brigid Kosgei and New York winner Mary Keitany, all from Kenya eyeing the title and its 5 million shillings (50,000 U.S. dollars) prize.

Moreover, Cheruiyot and Ethiopia's Roza Dereje are on 16 points apiece in the World Marathon Majors (WMM) series standings following their second-place finishes in Chicago and New York.

Winner of the series pockets 250,000 dollars and selects a charity of their choice to spend a similar amount.

"It was a great moment for me winning last year's London Marathon and I am very much looking forward to returning in April," said Cheruiyot.

"My aim was to run under two hours and 20 minutes, maybe 2:19, so I'm happy because I did 2:18."

Cheruiyot clocked two hours, 18 minutes and 31 seconds, her personal best time so far, to seal her London triumph last year ahead of three-time winner and race favorite Keitany, who finished fifth.

"The line-up for this year's race is, once again, incredibly strong so I know I will need to be at my very best to repeat last year's victory but it is a challenge that I'm really looking forward to. I will be ready," said a confident Cheruiyot.

From Ethiopia, the Kenyan troop will have to contend with Berlin Marathon bronze medalist Tirunesh Dibaba, Tadelech Bekele and Roza Dereje, who was second to Kosgei in Chicago.