Double gold for Dutch as China pull away in world medals hunt
On a night of first-time world champions, Marrit Steenbergen won the 100m freestyle to claim the first Dutch world title in the pool since 2013.
Barely 45 minutes later, Tes Schouten added another in the women's 200m breaststroke.
Teenager Dong Zhihao won the men's 200m breaststroke with a late surge and the Chinese men's 200m freestyle relay team ended the evening by taking gold.
China pulled further away at the top of the medal table, five months ahead of the Paris Olympics.
Spaniard Hugo Gonzalez also struck in the closing metres to take the 200m backstroke gold.
Steenbergen, a bronze medallist in the event at the championships last year, won in 52.26sec.
"Today I did not really feel the pressure," Steenbergen said. "I was just trying to have fun and I tied to enjoy the race. When I do that I can swim really fast."
She finished 0.30sec faster than Hong Kong's Siobhan Haughey, last year's silver medallist, and a gold medallist in the 200m earlier this week. Australian Shayna Jack was third.
Haughey led at the turn with Steenbergen in fourth, but the Dutchwoman surged through the field on the second lap to record the eighth fastest time in history.
Steenbergen collected her second gold medal of the week after helping the Netherlands to victory in the 4x100m freestyle relay.
Earlier in the competition the 24-year-old broke the 2015 national record held by Femke Heemskerk, a relay gold medallist at the Beijing Olympics in 2008. Steenbergen also ended a 11-year wait since Ranomi Kromowidjojo won a 50m free world title.
"I'm happy to be faster than them," Steenbergen said. "It feels really weird. Femke is an Olympic champion and it feels like she's a lot bigger than me."
Last year's winner, Australian Mollie O'Callaghan, is not competing in Doha, but is due to swim in Paris.
In the next final, Schouten won the women's 200m breaststroke.
Schouten, a bronze medallist last year, also broke her own national record. She led from the start to win in 2min 19.81sec, the ninth fastest time ever in the event.
Schouten said she had heard the Dutch national anthem playing for Steenbergen as she prepared to swim.
'Happy tears'
She wept after her victory.
"Happy tears," she said. "You have loads of nerves and it turned out good: a PB (personal best) and a gold. I saw my coach and I said: 'I'm so tired! I'm so happy!' I was all over the place."
Versatile American Kate Douglass was 1.10sec behind even though she hardly had time to dry off after finishing fourth in the earlier freestyle final.
Canadian Sydney Pickrem was third.
Dong powered from sixth to first in the final 50m, taking his first world title in a personal best time of 2:07.94.
Dutchman Caspar Corbeau, who led until the final 15m, took silver 0.30sec behind. American Nic Fink finished strongly to take bronze.
Gonzalez claimed a first world title with a strong final lap, overhauling Swiss swimmer Roman Mityukov to win by 0.10sec in 1:55.30.
"It could have been him or me," said Gonzalez. "Happy it happened to be me."
South Africa's Pieter Coetze came from eighth at the final turn to take bronze.
China, with men's 100m champion Pan Zhanle swimming the third leg, won the 200m relay in 7:01.84sec, just 0.10 ahead of South Korea with the United States third.
For China, which dominated the diving and artistic swimming, it was a sixth medal in the pool.
Overall they have 31 medals, 22 of them gold. The United States are second with 18 total medals, seven gold.