The 35-year-old Mary, a mother of three and a pre-tournament favourite for the gold, rewrote the record books when she eclipsed her joint haul of five golds with Katie Taylor of Ireland.
The Manipuri pugilist, who went over her weight category to clinch a 51kg bronze at the London Olympics, previously clinched the World Championship gold on five occasions -- 2002, 2005, 2006, 2008, 2010 -- besides bagging a silver on her debut in 2001.
Welcomed by thunderous chants of "Mary Mary" at the jampacked K.D. Jadhav hall, the Indian took the ring with a statistical and psychological advantage over her Ukrainian opponent, whom she recently beat at the Silesian Women's Open semi-finals in Poland.
Living up to the reputation, Mary started the opening round aggressively and landed a couple of right jabs quite early into the round before taking full control with a right-two punch combination to Hanna.
However, towards the end of the first round, the Ukrainian managed to get a shot on Mary's face before the Indian wrestled Okhota to the ground. Mary appeared unshakable throughout and ended the round with a few jabs and a right-hand, left-hand combo.
The Indian came back with more aggression in the second round, and started with a powerful hook with her right and then doubled the attack with two quick right jabs to leave her opponent rattled.
A left-handed flick from Okhota pushed Mary backwards but towards the end of the round, the Indian delivered a perfect right hook to inch closer to another gold.
The third and decisive round began with the Manipuri pugilist delivering a right-handed jab, and adding it up with a right-hand, left-hand combo that completely demotivated Okhota.
Mary then sealed the gold in her favour with another combination of punches, and a few shots at Okhota's face leading the crowd to erupt in joy when the referees announced the unanimous 5:0 verdict in the Indian's favour.
Advancing to the medal round, along with Mary Kom, were Shiksha (54kg) and Priyanka Chaudhary (60kg).
Mary Kom, a five-time world champion and an Olympic bronze-medallist, defeated Chinese Taipei's Meng-Chieh Pin in a split verdict in the quarterfinals to make the last four stage of the light flyweight (48kg) category.
The 34-year-old, who has won four gold and a silver medal in her five previous appearances at the event, will face Japan's Tsubasa Komura in the semi-finals on Tuesday.
The medal assured today is Mary Kom's first in more than a year and a massive confidence-booster for the boxer, who had missed Olympic qualification last year.
"It feels wonderful to get my sixth medal at this Championship. It hasn't been easy for me but God has been kind to ensure that I have managed to perform. This is my first medal in more than a year and the first after I became an MP," Mary Kom told PTI.
"It really does mean a lot to me given that I juggle so many roles. I am simply ecstatic right now but I have two more fights to go before I get what I truly desire, a gold medal," said the mother-of-three, who is a Rajya Sabha MP.
In a rather cautiously-fought bout, neither the Indian nor her opponent was willing to launch too many attacks. The punches were few and far between at least in the opening three minutes.
However, the two boxers upped the intensity in the second round. Pin, also the taller of the two pugilists, was the first to move away from the waiting game and began using her left straights and right hooks rather effectively.
However, Mary Kom too raised her game against the nimble-footed Pin, who displayed impressive defensive tactics.
"I have beaten her in the past when she was in the 51kg category. Today, she seemed too cautious and didn't attack me much. I also played along and waited. This eventually worked for me quite well," Mary Kom said.
"She is an experienced boxer but I have a good measure of her game," she added.
The Manipuri went all out in the last round and more than made up for a patchy display in the opening round to get the judges' nod.
Shiksha, who belongs to the Railways Sports Promotion Board, was up next for the country, against Uzbekistan's Ferangiz Khoshimova. The national champion took an attacking approach from the first ring of the bell and hardly gave her rival any breathing space.
The unrelenting aggression eventually fetched Shiksha a unanimous verdict in her favour from the judges. Shiksha will face Chinese Taipei's Lin Yu-Ting in the semifinals.
Priyanka too was a dominant force in her clash against Sri Lanka's Dulanjani Lankapurayalage and had no trouble earning a 5-0 victory.
However, world championships silver-medallist Saweety Boora (75kg), up against Olympic bronze-medallist Li Qian, bowed out after losing 0-5.
The Olympic bronze medallist pugilist decimated Australian April Franks 5-0.
The 36-year-old Indian had also won a gold medal at the India Open boxing tournament in May, but skipped the Asian Championships as part of a larger plan to enhance her chances of Olympic qualification.
The Asian Championship was held in Thailand in May.
Fresh from winning the gold at the India Open two months ago, Mary Kom participated in this prestigious tournament with the aim of testing herself and getting some much-needed bouts under the belt ahead of the World Championships.
Mary Kom, who claimed her sixth world title last year in Delhi, will be looking to qualify for the 2020 Tokyo Olympics in the World Championships in Yekaterinburg, Russia.
The 2019 World Boxing Championships for women will be held from September 7 to 21.
Mary Kom shared the image of the certificate of recognition on her official Twitter handle and wrote, "Thank you so much for the recognition" tagging WOA and International Olympic Committee (IOC).
'OLY' signifies sportspersons' ongoing role in society as an Olympian, living and promoting the Olympic values. In November 2017 at the eighth International Olympic Committee (IOC) International Athletes' Forum, the WOA announced the OLY post-nominal letters initiative.
The initiative allows Olympians to use the OLY lettering on any official documentation after their name much like when one gets a degree.
In the Women's World Boxing Championships held in Ulan-Ude, Russia last month, the ace Indian pugilist had to settle for bronze medal after she lost her semi-final bout in the 51-kg flyweight category to second-seed Busenaz Cakiroglu of Turkey in a split verdict.
The London Olympic bronze medallist is the only boxer across male and female categories to collect eight World Championships medals.