Britain's Sir Mo Farah admitted he needs to improve if he is to win an Olympic medal at Tokyo 2020 as he prepares to race at the Virgin London Marathon for the first time in four years.
The 35-year-old, a four-time Olympic gold medallist and six-time world champion, called time on his track career in 2017 to focus on the longer distance.
Sir Mo last competed at the London Marathon in 2014, where he finished eighth, and will make his return to the famous race on Sunday (April 22).
He is targeting gradual improvement in the lead-up to Tokyo 2020 but believes he can break the British record of 2 hours 07min 13sec set by Steve Jones 33 years ago.
"Until I finished on the track I’ve been improving step by step and I think it’s going to be the same with the marathon," Sir Mo said here today.
"If I’m going to come away with a medal from Tokyo then, each year, if I can run two marathons that would give me good confidence and I can learn about myself – the things you can do and can’t do.
"That’s why I had a great track career - I learned how to win races, put off the opposition and be strong mentally and physically.
"I think, in the marathon, physically I am strong and mentally I have to start practicing."
Sir Mo conceded victory during Sunday's race was unlikely owing to the strength of the field, which includes the Kenyan duo of Eliud Kipchoge and Daniel Wanjiru.
Kipchoge is a two-time winner of the event and also won the Olympic marathon at Rio 2016, while Wanjiru is the defending London champion.
"The field is strong but our aim is to go with our own plan and see what we can do," Sir Mo said.
“The aim is to go after the British record for sure but, at the same time, in my mind since 2014 until now I’ve learned more and understand a lot more.
"We’ll see what happens.
"A win would be amazing for me but obviously this is going to be different.
"Every race I go into, I go into it to fight and go for the podium.
"Anything can happen in the marathon."
Sir Mo admitted he watched Uganda's Joshua Cheptegei win gold in the 5,000 and 10,000 metres - races Farah dominated during his track career - at the Commonwealth Games in the Gold Coast.
"I watched and I wondered whether I could have done that double," he said.
"But as an athlete you have to set yourself new challenges.
"You have to enjoy what you do."