There’s only one person in the world now who can influence Putin, says Stephen Roach

Stephen Roach said that the best thing that China could do right now is to broker a peace deal between Russia and Ukraine.

There is only one person in the world who has leverage over Putin, and that is the Chinese President, according to Roach.

China is holding the trump card here and I think it's up to Xi to seize the moment.

Putin has not let up in the fighting in Ukraine.

The U.S., U.K. and European Union have imposed sanctions on Russia. China won't participate in sanctions and won't call Russia's attack on Ukraine an invasion.

China abstained from voting in the UN resolution.

Beijing has instead promoted negotiations and positioned itself further away from Russia than was portrayed in early February during a high-profile meeting between Xi and Putin. On the opening day of the Winter Olympics in Beijing, the leaders made a promise to work against the West.

If Putin doesn't play ball, Roach said that China should threaten to pull the rug out. Roach said that China would be branded guilty by association for a long, long time.

Roach said that he cannot afford to stay that course and that it would be a mistake of historic proportions.

CNBC's Evelyn Cheng contributed to the report.