Sacramento - Rising sprint star Christian Coleman made an explosive start to his US World Championship trials campaign on Thursday, romping into the 100m semi-finals in under 10 seconds as fastest qualifier.
The 21-year-old prodigy from the University of Tennessee shrugged off searing temperatures of around 43 degrees Celsius at Sacramento's Hornet Stadium to advance in 9.93.
Coleman already owns the fastest time in the world this year over 100m, scorching to 9.82 at the US collegiate championships.
"I felt pretty good. I just wanted to come out here and get through the rounds and execute and do the best I can," said Coleman, who eased up significantly in the closing stages of an easy win.
"I feel like I still have something," he added.
Isiah Young was second fastest in qualifying, clocking 9.97 while evergreen veteran Justin Gatlin shrugged off niggling injuries that have disrupted his season to be third quickest in 10.00.
"Track is fast," said Gatlin. "It's a surreal time for me. This is the most injured I've ever been but I'm just fighting through man."
But there was an early exit for another veteran, Tyson Gay.
The 34-year-old American record holder is competing in Sacramento just eight months after the shooting death of his teenage daughter in October last year.
Gay, who has dedicated this season to his daughter's memory, could only finish third in his heat in a time of 10.17, 15th overall.
In the men's 400m meanwhile, Texas A&M star Fred Kerley served notice of his talent with a nonchalant win in his heat.
Kerley, 22, astounded the track world last month with the seventh fastest 400m in history, a world-leading 43.7.
Few would bet against Kerley adding another fast time this weekend after his performance on Thursday when he coasted over the final 30m to win in 45.13.
"I've got plenty of gas in the tank," Kerley told AFP.
"I've put in the work. With practice you can do anything. My goals this season? To win. Win everything I'm in. Every level."
In the women's 100m, US track queen Allyson Felix made a rare appearance over the shortest sprint distance to advance in 11.03.
Felix, who is already assured of a place in the US team for London by virtue of her status as the reigning world 400m champion, is using the 100m and 200m in Sacramento to improve her speed.
"I plan to run the 100m and 200m here," Felix said. "My focus at worlds is on the 400m for sure. We'll see what happens as far the relays go," added Felix, the only woman track and field athlete to win six Olympic gold medals.
The top three finishers in each event at the four-day meeting in northern California will qualify for the US team for the World Championships in London in August, providing they meet qualifying standards.
Meanwhile the brutal temperatures did not deter US 800m runner Alysia Montano - five months pregnant - from racing.
Montano, 31, finished last in her 800m heat in 2:21.40, but was all smiles afterwards as she revealed that her decision to run had been partly inspired by the hit Hollywood superhero movie "Wonder Woman" starring Gal Gadot.
"I feel amazing," said Montano, who ran in a vest emblazoned with the iconic comic book character.
"I thought it (Wonder Woman) was amazing," Montano said. "And then I found out that (Gadot) did half of the movie five months pregnant so I thought 'I will definitely be signing up for US Nationals'."
Selected results from US World Championship trials at Hornet Stadium, Sacramento on Thursday:
1. Hassan Mead 29min 01.44
2. Shadrack Kipchirchir 29:01.68
3. Leonard Korir 29:02.64
4. Biya Simbassa 29:03.48
5. Galen Rupp 29:04.61
6. Diego Estrada 29:08.14
7. Sam Chelanga 29:08.29
8. Chris Derrick 29:12.58
9. Tyler Day 29:22.66
10. Matthew McClintock 29:22.83
1. Alex Young 73.75
2. Johnnie Jackson 71.69
3. Sean Donnelly 71.45
4. Rudy Winkler 71.43
5. Colin Dunbar 71.21
6. Kibwe Johnson 70.09
7. Darien Thornton 67.72
8. Jordan Crayon 67.05
10 000m final
1. Molly Huddle 31min 19.86
2. Emily Infeld 31:22.67
3. Emily Sisson 31:25.64
4. Shalane Flanagan 31:31.12
5. Natosha Rogers 31:54.62
6. Erin Finn 32:00.46
7. Liz Costello 32:28.05
8. Stephanie Bruce 32:45.43
9. Elaina Balouris 32:48.76
10. Alia Gray 33:16.54
1. Kara Winger 62.80
2. Ariana Ince 58.32
3. Rebekah Wales 55.28
4. Dominique Ouellette 53.54
5. Channing Wilson 53.03
6. Alyssa Olin 51.58
7. Madalaine Stulce 51.24
1. Keturah Orji 14.26
2. Tori Franklin 13.80
3. Andrea Geubelle 13.62
4. Viershanie Latham 13.34
5. Amber Hughes 13.32
6. Tiffany Flynn 13.30
7. Tony Smith 13.24
8. Blessing Ufodiama 13.20
1. Gia Lewis-Smallwood 62.65
2. Whitney Ashley 62.20
3. Valarie Allman 57.93
4. Rachel Dincoff 56.91
5. Kelsey Card 56.84
6. Summer Pierson 56.70
7. Liz Podominick 55.20
8. Katelyn Daniels 54.83