Olympic stars Sydney McLaughlin-Levrone and Noah Lyles headline a star-studded line-up as the US Track and Field Championships get underway on Thursday with places at the Tokyo World Championships up for grabs.
Four days of high-calibre competition begin at Hayward Field in Eugene, Oregon, with an array of Olympic gold medallists and reigning world champions on duty.
Many of the biggest names in the field – such as Olympic 100m champion Lyles – have already secured their tickets to the World Championships in September due to their status as reigning world champions.
However there remain plenty of unanswered questions as the competition at the spiritual home of US athletics begins.
Arguably the most intrigue surrounds two-time Olympic 400m hurdles champion McLaughlin-Levrone, who has not lost in her signature event since 2019.
The 25-year-old cemented her status as the greatest women's 400m hurdler in history a year ago in Paris as she stormed to her second Olympic gold in the event in a world record 50.37sec.
But McLaughlin-Levrone has raised eyebrows heading into this week's meeting by electing to skip the 400m hurdles and concentrate on the 400m flat instead.
It means that McLaughlin-Levrone, who missed the 2023 Budapest world championships with a knee injury, risks missing out on competing in the hurdles in Tokyo, although she could still qualify for the event with victory in the Diamond League finals in August.
ALL EYES ON RICHARDSON
In the women's short sprints, meanwhile, all eyes will be on reigning 100m world champion Sha'Carri Richardson.
Richardson's upset victory in Budapest two years ago means she is assured of a place in the field in Tokyo.
But this week's event offers observers a good barometer of Richardson's form and fitness as he prepares to defend her title in Japan.
The 25-year-old has struggled to find her best form in two outings in the 100m so far this season, her best time a modest 11.19sec – ranking her 96th in the world – at the Prefontaine Classic, also held at Hayward Field, earlier this month.
The opening heats of the 100m take place on Thursday, with the final due on Friday.
Richardson may well find herself in the slipstream of rising star and training partner Melissa Jefferson-Wooden, who owns the fastest time in the 100m this year at 10.73sec.
Richardson and Jefferson-Wooden are also entered in the 200m, where they will face Olympic champion Gabby Thomas, silver medallist at the 2023 Worlds in Budapest.
In the men's sprints, the pressure is off for reigning 100m and 200m world champion Lyles.
But the charismatic Olympic champion will be looking for signs of a return to form after losing his first 100m of the season at the Diamond League in London on July 19 as he works his way back from an ankle tendon problem.
Lyles can expect stiff opposition from a resurgent Kenny Bednarek in the 100m, with veteran Trayvon Bromell also in the mix.
Elsewhere, the men's 400m has been opened up by the withdrawal of Olympic champion Quincy Hall, while the women's 800m sees a return for Tokyo Olympics gold medallist Athing Mu-Nikolayev, a late entry to the trials.
In the men's 110m hurdles, three-time world champion and reigning Olympic champion Grant Holloway is in action.
Women's 100m hurdles Olympic champion Masai Russell is also aiming to secure her place in Tokyo.