Olympic champion Tuvshinbayar Naidan of Mongolia was back to his best as he stormed into the semi-finals of the men's judo under-100kg category Thursday.
In the intervening four years, Naidan has struggled to match his Beijing performance but he was back on form at London's ExCel Arena.
The 28-year-old strangled Teerawat Homklin of Thailand in the first round before beating France's Thierry Fabre by the maximum ippon score.
His toughest test came in the quarter-finals against Ramziddin Sayedov of Uzbekistan.
The pair were inseparable after five minutes of combat but just 15-seconds into a sudden death period of golden score, Naidan flipped Sayedov over his head and flat on his back with a seoi-nage (shoulder throw) to win.
He will next face South Korea's Hwang Hee-Tae, the 2003 world champion.
Hwang is 34 now and has had few results to match his world title but, just like 33-year-old compatriot Song Dae-Nam, who won the under-90kg gold medal on Wednesday, he seems to be enjoying a late flourish to his competitive career.
He took advantage of world number one Maxim Rakov of Kazakhstan being stunned by 21-year-old Elmar Gasimov of Azerbaijan, who threw him for a minor yuko score with a hip throw.
Hwang was given a hard time by Gasimov but prevailed courtesy of a hip throw for yuko.
On the other side of the draw, world champion Tagir Khaibulaev of Russia survived a scare against Czech Lukas Krpalek to make the semi-finals.
Krpalek was leading their fight with a minute left by a yuko and in a ground battle was trying to roll his opponent into a position from which to effect an arm-lock.
Yet he made a mistake and Khaibulaev, who until then was merely defending, suddenly found an opportunity to turn things around, managing to roll the Czech onto his back and pin him for ippon.
Krpalek had earlier shocked third seed Takamasa Anai of Japan, pinning him for the necessary 25-seconds needed to win.
Second seed Henk Grol of the Netherlands was upset in the quarter-finals by Germany's Dimitri Peters with a tani-otoshi (valley drop) technique that scored a half-point waza-ari.
In the women's under-78kg division world champion Audrey Tcheumeo of France beat Olympic champion Yang Xiuli of China to set up a fight with Britain's Gemma Gibbons in the last four.
Tcheumeo edged past Canada's Amy Cotton with a yuko from a foot sweep (de-ashi-barai) and then flattened Ukraine's Maryna Pryshchepa with osoto-gari (major outer reap) in just 34 seconds.
In the quarter-finals she scored a waza-ari with sumi-gaeshi (corner throw) to knock-out Yang.
Outsider Gibbons, who only qualified for the Olympics by virtue of being a home fighter, upset the apple-cart to reach the semis.
She threw Portugal's Yahima Ramirez with a delightful uchi-mata (inner thigh throw) for ippon in her first round and then left it late in her next two fights.
She scored a winning yuko against Mongolia's Lkhamdegd Purevjargal with just one second left on the clock and then scored a waza-ari to beat former world champion Marhinde Verkerk of the Netherlands with an ouchi-gari (major inner reap) with just 12 seconds left.
Verkerk had earlier beaten second seed Akari Ogata of Japan, turning around the fight 20 seconds form the end.
In the other semi-final former world champion Kayla Harrison of the United States will face Brazil's Mayra Aguilar.