2 Canadian track stars have a big Olympic tuneup on Friday

One of the last important track and field meets before the Olympics takes place Friday in Monaco, where Canadian stars Marco Arop and Christopher Morales Williams are among the big names at this week's Diamond League tour stop. Here's who and what to watch:

Marco Arop in the men's 800m at 2:23 p.m. ET

The reigning world champion is undefeated in three 800m starts this year, including a Diamond League win in China in April and a dominant victory at last month's Canadian Olympic trials.

On Friday, Arop was slated to face his main rival, 19-year-old Kenyan Emmanuel Wanyonyi, who took the silver at last summer's worlds in Budapest before beating Arop in the Diamond League final in Oregon a few weeks later. But Wanyonyi dropped out after suffering his first defeat since the world championships, finishing second to Algeria's Djamel Sedjati in a photo finish at last Sunday's Diamond League meet in Paris.

"The world record is within reach"<a href="https://twitter.com/marco_arop?ref_src=twsrc%5Etfw">@marco_arop</a> thinks something very special is brewing in the men's 800m ahead of <a href="https://twitter.com/Paris2024?ref_src=twsrc%5Etfw">@Paris2024</a>...<a href="https://twitter.com/hashtag/MonacoDL?src=hash&amp;ref_src=twsrc%5Etfw">#MonacoDL</a>