"When we got to Athens, the first thing he said was, 'You are on your own.' The night before the 400m race, he spent the whole night clubbing and during the event he almost fell ... he was more tired than I was!" she said.
Despite the near mishap, Guilhermina took the bronze medal in the 400m -- but finished down the field in the other two events.
She realized that she was competing in the wrong races, and swapped the two longer ones for sprints over 100m and 200m.
It proved an inspired move and, once she had mastered the skill of driving out of the starting blocks, Guilhermina never looked back.
A world record in the 100m for her category came in 2007 and she won a full set of medals at the Beijing Paralympics the following year.
Her defeat in 100m was a disappointment though, as Chinese runner Wu Chunmiao won gold. "I was slow getting out of the blocks and I stumbled."
But Guilhermina made amends in the 200m to win her first Paralympic gold, and repeated her bronze of Athens in the 400m.
Coming into London 2012, Guilhermina was ever more confident, particularly because of the ability of her guide runner, Guilherme Soares de Santana.
He is her seventh, having come together in 2010.
"He's the best guide in the world because I'm not aware of him on the track. Guilherme has given me back the feeling of running by myself. That's the best gift I could have."
The ultimate goal for 2012 was a hat-trick of Paralympic golds and, after a comfortable win in the 200m, they seemed on track.
Then disaster struck in the 400m, in one of the most heartbreaking moments of the Games.
The pair looked set for victory when Soares de Santana fell in the finishing straight, pulling down Guilhermina in full flight.
The capacity crowd gasped in disbelief as France's Assia El Hannouni crossed the line first while the Brazilian pair lay prone on the track.
In defeat, Guilhermina had made the headlines and highlighted the fine line between success and failure in disability sport.
"I felt literally blind in that moment, and that moment, he stopped being invisible to me," she recounted.
But it was to be expected that Guilhermina would not let that setback derail her ambitions and the very next day, still "very sore from all the previous races," she stormed to victory in the 100m in a world-record time of 12.01 seconds.
Honor was restored after the bitter disappointment of just 24 hours previously, and she and Soares de Santana shared the glory on the podium.
"We are a team. If we lose we do it together, and if we win ... we win together," she said proudly.
Despite her advancing years -- she will be pushing 38 by the time of the Rio Paralympics -- Guilhermina is absolutely determined to compete in her three events in front of home fans and achieve the hat-trick which so cruelly eluded her.
"I'm going to take care of myself so that in Rio I can win gold medals in every race I compete. I intend to do better than London when it comes to my times."
The inspiration is performing for the last time in front of her home fans and being a role model for the next generation.
"I feel honored to be an example for others," she said.