The Prefontaine Classic, divided between Distance Night on Friday and the main Saturday schedule at Hayward Field in Eugene, Oregon, has the best middle-distance and distance races of any American track meet. Here are five key races to watch. We’ll publish full reports of each day’s action over the weekend.

Men’s 10,000 Meters, Friday
Mo Farah’s 10K victory at the 2011 Pre meet marked his emergence as a world beater; he’s now the reigning Olympic and world champion at 5000 and 10,000 meters. Friday’s 10,000 will be an early indicator of how capable he’ll be of defending his two world titles in August.

Galen Rupp won last year’s 10,000 in an American record 26:44.36, faster than his Farah’s PR of 26:46.57. In a stronger field on Friday, Farah primarily needs to worry about winning, so Rupp’s ownership of the Nike Oregon Project PR in this event may stand.

Paul Tanui of Kenya, the 2013 World Championships bronze medalist, has a 26:49.41 personal best but he couldn’t handle Rupp’s kick a year ago, and will likely have troubles with Farah’s on Friday. Farah may get his true test from Geoffrey Kamworor, Kenya’s world champion in cross country and the half marathon.

Men’s 5000 Meters, Friday
The primary mission here involves getting the World Championships qualifying standard of 13:23.0 or better. The Americans in the field—Galen Rupp, Bernard Lagat, and Ryan Hill—haven’t made the time yet, mainly for lack of opportunity.

This 5K may not be as fast as 2012’s, when Rupp set his PR of 12:58.90 while finishing third. But it won’t be slow. Among Rupp’s challengers will be Edwin Soi, the Kenyan who defeated Mo Farah in the Prefontaine 5000 in 2013, and Isiah Koech, the 2013 World Championships bronze medalist with a personal best of 12:48.64.

Women’s 1500 Meters, Saturday
Jenny Simpson and Shannon Rowbury have built a compelling rivalry for American supremacy in this event. Simpson got the edge by 1/100th of a second as feet got tangled at the finish of a Zurich 1500 in 2014, a year in which she broke 4:00 three times and Rowbury did so twice. Simpson was also the 2014 Diamond League series winner in the event.

The Simpson-Rowbury matchup could be a tense crowd pleaser, but both women need to watch out for Sifan Hassan of the Netherlands, fastest in the world last year.

Women’s 5000 Meters, Saturday
Genzebe Dibaba set the world indoor 5000 record of 14:18.86 in February. The outdoor record of 14:11.15 belongs to her older sister Tirunesh, a multiple Olympic champion. Genzebe Dibaba’s coach thinks she can run 14:10, but no one’s saying Saturday will be the day that happens.

A Dibaba triumph is far from guaranteed. The field includes Sally Kipyego and Betsy Saina, two former NCAA champions now thriving as pros, and 2011 5000- and 10,000-meter world champion Vivian Cheruiyot, on the way back to peak fitness after childbirth.

American fans will watch to see if Molly Huddle can bridge the gap to the Africans; her American record is 14:42.64.

Men’s Bowerman Mile, Saturday
The Bowerman Mile is now the most important outdoor men’s mile in the world. Ayanleh Souleiman of Djibouti won last year in 3:47.32, the fastest mile in the world since 2007, and Kenya’s Silas Kiplagat was next in 3:47.88. Those two and Olympic and World Champion 1500-meter gold medalist Asbel Kiprop are returning on Saturday. Kiplagat, who comes off a Shanghai Diamond League victory in the 1500 on May 17, might rate as a slight favorite.

Aman Wote of Ethiopia and little-known Ronald Kwemoi, who ran 3:28.81 for 1500 meters in 2014, could pull an upset. Americans Matthew Centrowitz and Leo Manzano, silver medalists in the World Championships and Olympics, respectively, need to stay in range for what should be a furious finish for whoever’s survived the pace to that point.

Friday night’s races will be streamed live on USATF.tv, starting at 8 p.m. Pacific/11 p.m. Eastern. Saturday’s races will be broadcast on NBC at 1:30 p.m. Pacific/4:30 pm. Eastern.