Bukov wins 50m freestyle gold for Ukraine, Sjostrom reigns again in butterfly
With six golds up for grabs in the evening programme, American Claire Curzan completed a rare backstroke treble by winning the 200m, while Italian distance queen Simona Quadarella took 800m freestyle gold in a thriller.
The 21-year-old Bukhov stormed home in 21.44 seconds to pip Australian favourite McEvoy by 0.01 seconds and win his first world title.
Based in Kyiv, Bukhov said the war with Russia had made training dangerous.
"It's hard, really hard," he told reporters.
"We train while Russian rockets are flying around swimming pools or other training buildings. So you never know still if you are alive or not."
McEvoy, who took a bonus 50m butterfly bronze in Doha, had his slowest swim in the freestyle final after a sizzling 21.13 in the heats and 21.23 in the semi-finals.
"Mixed emotions," said McEvoy, who has revived his career over the past year with a scaled-back training regime.
"Of course, you want to get the gold medal... Regardless of missing the gold by 0.01, I can't look back at where I've come from and be disappointed with that."
The evergreen Sjostrom ignited the night with her win in the non-Olympic 50m butterfly, producing a scintillating swim of 24.63 seconds, only two-tenths of a second shy of her world record (24.43) and the third fastest ever.
Thrashing French runner-up Melanie Henique by nearly a second, Sjostrom became the second swimmer to win six consecutive world titles, with American great Katie Ledecky the first in the 800m freestyle at Fukuoka last year.
She also extended her record world medals haul in individual events to 22 and could add another when she defends her 50m freestyle title as the top seed on Sunday.
"That's amazing, I'm very happy with the race and that I was able to win again," said the Swede.
"I'm just enjoying it... I'm very excited for the rest of the year and also getting married this year, so it's going to be exciting."
Seasoned Egyptian Farida Osman took bronze, her third world medal and first in nearly five years.
CURZAN CASHES IN
Hampered by an untimely illness, Curzan narrowly missed out on the US team to Fukuoka last year but has filled her boots in Doha in the absence of the biggest names in backstroke.
Having already wrapped up the 50 and 100 titles, the 19-year-old smashed her personal best to win the 200m in 2:05.77, more than a second clear of Australia's Jaclyn Barclay.
Curzan became the second swimmer to sweep the women's backstroke events, following Australian Kaylee McKeown last year at Fukuoka.
The Virginia University swimmer now has six medals from Doha, earning $75,000 alone for the individual ones.
"I don't think I could have scripted a better meet," she told Reuters.
"Definitely (having) a shopping trip. I've been jealous of all my friends' wardrobes at college."
Ledecky gave up her 800m title by skipping Doha but the crowd was treated to a thrilling battle between Quadarella and Isabel Gose.
The duo swapped the lead repeatedly in the final lap before Quadarella touched in 8:17.44, 0.09 seconds ahead of German Gose.
Like Curzan, 19-year-old Ribeiro has capitalised on big names skipping Doha.
Having won the 50m butterfly, he clocked 51.17 to win the 100m, edging Austria's silver-winning Simon Bucher. Veteran South African Chad le Clos was fifth.
A young Chinese team, spearheaded by 100m freestyle world record holder Pan Zhanle, rounded off the night by winning the mixed freestyle relay in 3:21.18 ahead of Australia and third-placed United States.
Defending champion Ahmed Hafnaoui crashed out of the men's 1,500m freestyle heats earlier on Saturday, having also missed the 400m and 800m finals.
Sunday's 1,500m final, nonetheless, promises to be tight, with only a few seconds separating the top qualifiers led by German Florian Wellbrock, the Olympic bronze medallist, who clocked 14:48.43.