Gareca, whose side beat New Zealand 2-0 in Lima to qualify by the same score on aggregate via an inter-confederation playoff, was cruelly denied the chance to take part in the 1986 World Cup finals as a player for eventual champions Argentina.
In 1985, the then striker scored the goal that guaranteed his home nation their place in Mexico, ironically against Peru, the team he would come to manage three decades later.
However, Gareca did not make the final squad that, thanks largely to Diego Maradona's guile and brilliance, would lift the title at the Aztec Stadium. He was dropped, an experience he later described as one of the most bitter of his career.
Now, the man known as 'The Tiger' can look forward to a summer in Russia, with a team he has patiently built back to something resembling its best.
"Mission accomplished, thank you," Gareca said after goals from Jefferson Farfan and Christian Ramos gave Peru a historic victory. "We have managed something very important for the country. I am very emotional."
After coaching a slew of South American clubs, Gareca was hired as Peru manager in 2015 with the express task of taking a national side that contained plenty of talent but few big names back to the finals for the first time since 1982.
His two-and-a-half years in charge started inconsistently and some Peruvians, unwilling to forget his decisive goal in 1985, were quick to call for his head.
"It was a complicated start," Gareca admitted. "You always need a bit of luck. I am a person who believes in luck, although I believe in work above all."
He led Peru to the semi-finals of the 2015 Copa America but they struggled in the early World Cup qualifiers, winning just one of their first six fixtures.
However, they were given a huge boost in September last year when in their seventh match, Bolivia fielded an illegal player and the 2-0 defeat was overturned into a 3-0 victory by a sporting tribunal.
The decision sparked a run of form that lifted the Andean nation up to fifth place in the South American qualifying table, guaranteeing them a playoff spot against New Zealand.
Both goals in the tie came in Lima on Wednesday and extended the side's unbeaten run to 10 games, the longest any Peru team has run up in 75 years.
Gareca will hope the run can continue and that in Russia, he can finally show the world what they were missing.
(Additional reporting by Marco Aquino; Editing by John O'Brien)
