The Americans took victory in the men's and women's 200m respectively in hotly-anticipated races, with Lyles facing Olympic champion Andre de Grasse of Canada and Thomas coming up against 2019 world champion Dina Asher Smith of Great Britain.
On a windy, blustery evening in the Qatari capital, which claimed the men's pole vault as it was too dangerous to vault in the strong winds, Lyles and Thomas shone – with the latter equalling the meet record in her race after the wind died down below the legal limit.
There was also joy for Grenada's Anderson Peters, who broke the 90-metre mark in men's javelin for the first time and set a new Americas continental record with a throw of 93.07m, good for fifth on the all-time list.
Earlier, the meet record also fell in the men's 400m hurdles to Brazil's Alison dos Santos.
You can re-live all the action from Doha in the Olympics.com live updates, below.
Most recent updates are displayed first; all times are local time (UTC +3 hours)
8:55pm – El Bakkali wins in photo-finish
The final Diamond League race of the night is the men's 3000m steeplechase.
This race starts off very tactical and it's not until the last lap when Sofiane El Bakkali, the Olympic champion, and Ethiopia's Lamecha Girma make a move.
The Moroccan and Girma are neck-and-neck all the way as El Bakkali out-sprints Girma to take it at the line in 8:09.66, one-hundredth of a second in front of the Ethiopian.
Kenya's Abraham Kibiwot is third.
8:47pm – Anderson Peters breaks Americas area record in javelin
Wow! What an awesome show from Grenada's javelin thrower Anderson Peters, who re-writes his national record three times today and also breaks the Americas area record.
Peters threw a mammoth 93.07m on his final attempt – bettering his season's best by nearly nine metres. That's also the world lead.
He earlier threw 88.96m and 90.19m.
Olympic silver medallist Jakub Vadlejch of the Czech Republic also clears 90m, with a 90.88m effort a new personal best too for silver.
Germany's Julian Weber (86.09m) finishes third.
8:45pm – World indoor champ Woo takes men's high jump
After all the build-up featuring Olympic champions Mutaz Essa Barshim and Gianmarco Tamberi, it's the world indoor champion Woo Sanghyeok of South Korea who nips in to clinch men's high jump victory.
Woo cleared 2.33m, the only man to do so; Barshim was second on 2.30m with Canada's Django Lovett third at 2.27.
Tamberi was seventh, only clearing 2.20m.
8:36pm – Thomas ties meet record in women's 200m
Olympic bronze medallist Gabrielle Thomas, the third-fastest woman ever over 200m, just tied Allyson Felix's meet record to win the women's 200m.
The American clocks a wind-legal 21.98, her season's best, ahead of Jamaica's Shericka Jackson (22.07).
British star Dina Asher-Smith, returning to the site of her 2019 world title in this distance, comes home third.
8:28pm – Kipsang solid in 1500m
World leader Abel Kipsang leads home a Kenyan one-two in the men's 1500m.
The winning time of 3:35.70 is more than four-and-a-half seconds down on his year's best set last weekend at the Kip Keino Classic in Nairobi.
Timothy Cheruiyot does break his season's best though in second with a 3:36.16; Ethiopia's Teddese Lemi is third in 3:37.06.
8:12pm – Noah Lyles takes men's 200m win
In one of the most eagerly-anticipated races of the night, USA's Noah Lyles has taken the win in the men's 200m.
His 19.72 (just over the legal wind limit, with a +2.1m/s tailwind) was 0.03 quicker than teammate Fred Kerley; Olympic champion Andre de Grasse of Canada was edged out for third (20.15) by Trinidad and Tobago's Jereem Richards in a photo-finish.
8:03pm – Harrison powers home to win 100m hurdles in photo-finish
Kendra Harrison, the world record holder and Olympic silver medallist in the women's 100m hurdles, clocked a fast 12.43s to win the Doha race.
It was heavily wind-assisted though, with the gauge reading +3.8m/s.
Tobi Amusan of Nigeria and Britany Anderson of Jamaica dead-heated for second in 12.44.
An incredible photo-finish.
7:54pm – Kibet wins men's 800m
Unsurprisingly, the wind is continuing to wreak havoc today.
A slow men's 800m race is won by Kenya's Noah Kibet in 1:49.08, nearly six seconds off the world lead time.
Peter Bol of Australia and Marco Arop of Canada complete the top three.
Elsewhere, the men's high jump featuring Messrs. Tamberi and Barshim, and the men's javelin, are under way.
7:41pm – Dos Santos breaks meet record in hurdles
Wow, the track action is living up to its billing!
Alison dos Santos of Brazil storms home to win the men's 400m hurdles in a new world lead and meet record time of 47.24 seconds, breaking Rai Benjamin's mark in Doha from last year.
Benjamin himself crosses the line second in a season's best 47.49.
Ireland's Thomas Barr is third some way back in 49.67.
7:35pm – Ricketts wins heavily wind-affected triple jump
All over in the women's triple jump, where Jamaica's Shanieka Ricketts posted the best jump of 14.82 (+6.5m/s) on her third attempt.
The wind really messed with run-ups and the competition today, but that didn't put the Jamaican off.
World indoor silver medallist Maryna Bekh-Romanchuk of Ukraine takes second with a 14.73; Dominica's Thea Lafond gets third with a 14.46.
As for Patricia Mamona, she finished sixth.
7:25pm – Niyonsaba clinches 3000m flat
What a women's 3000m flat!
Burundi's Francine Niyonsaba, the Rio 2016 800m silver medallist who moved up to compete at 5000m (and won last year's Diamond League crown at that distance), clocks a world lead 8:37.70 to win the race.
She led nearly from the start and was ahead at the 1000m and 2000m splits.
That last lap was completed in 59.83 seconds. Kenya's Faith Kipyegon finishes just behind in second, in 8:38.05; Australian Jess Hull is third in 8:40.97.
7:15pm – Chase Ealey leads USA 1-2-3 in shot put
The women's shot put event is the first field event of the day to conclude, with American Chase Ealey topping the standings in a U.S. sweep of the top three spots.
Ealey's third throw of 19.51 metres bested the field, with Maggie Ewen's 19.32m in second.
Jessica Ramsey completed the top three with an 18.99m on her fourth attempt.
7:07pm – Paulino takes women's 400m
The Tokyo 2020 silver medallist in the women's 400m, Mariledy Paulino of the Dominican Republic, takes the season-opening Diamond League track race.
Her time's a 51.20, well clear of Stephenie Ann McPherson of Jamaica in second (51.69).
Bahamian star Shaunae Miller-Uibo was third in 51.84. That headwind really affected the athletes.
6:30pm – Women's triple jump headed by Mamona
The Tokyo Olympic Games silver medallist Patricia Mamona of Portugal is the headline name in the women's triple jump, with the world record holder Yulimar Rojas absent.
Rojas holds the meet record in Doha of 15.15m from last year, but all eyes will be on Mamona.
As a reminder, the 'final three' format – which previously saw the top three after five jumps progress to a single winner-take-all last jump – has been adjusted for this year.
The top three will still be the only ones in the final round, but their final-round result will no longer determine the winner, with all six rounds counting.
Mamona opens with a 14.07m – and to prove just how windy it is, she had a tailwind of +5.6m/s. The limit for records is +2.0m/s.
6:15pm – Men's pole vault cancelled due to high winds
Some unfortunate news to start off with today. The men's pole vault has been cancelled due to high winds in Doha.
Sadly, it's not safe for the vaulters to compete.