The popular Uruguayan made an almost instant impact at the club after taking over in October following Paolo Di Canio's sacking with the club bottom of the table, overseeing a dramatic win in only his second game in charge as his side beat Newcastle 2-1 thanks to a late strike by Fabio Borini.
More impressive wins followed, too, with Manchester City beaten at the Stadium of Light while both Chelsea and Manchester City were knocked out of the Capital One Cup.
Perhaps the nadir came in a 5-1 thrashing by Tottenham that was followed up by defeat to Everton on April 12 which left the Black Cats staring into the abyss, bottom of the table with the club's next three away matches at the Etihad Stadium, Stamford Bridge and Old Trafford. At that point the Black Cats were 1/12 with some bookmakers to go down.
Yet the loss against Everton marked something of a turning point for the Black Cats. Poyet had changed his formation for the clash with the Toffees, ditching his 5-3-2 formation, which seemed ill-suited to the players at his disposal, and reverting instead to a 4-5-1.
Despite defeat, a much-improved performance followed and indeed continued three days later as Sunderland, using the same formation, traveled to the Etihad to face Manchester City.
The much-maligned Connor Wickham was the man for the occasion that night, reminding everyone why Sunderland splashed out 8 million pounds to sign him from Ipswich back in 2011. Two goals in 10 minutes by the Englishman gave Sunderland a 2-1 lead but his ability to hold up the ball and allow Fabio Borini and Adam Johnson to receive it higher up the pitch was crucial. The Black Cats were only denied victory by an 88th-minute Samir Nasri equalizer.
A trip to Stamford Bridge followed where Poyet was welcomed by banners from the home fans reading: "Miracles happen Gus" - and, in west London, they did.
Wickham's influence on his side’s survival cannot be understated. Another two goals against Cardiff City gave Sunderland yet another win, while an assist for Seb Larsson ensured that the Black Cats beat Manchester United at Old Trafford for the first time in 46 years.
The striker's surge in form also saw him named player of the month for April and a goals-per-minute ratio (151.6) that eclipses both Romelu Lukaku (176.64) and Olivier Giroud (187.97) have led to calls for a late England call-up.
Borini has also profited and, together, the on-loan Liverpool man and Wickham have scored more goals in their last five games than Cardiff, Norwich City and Fulham combined. All of those teams will be playing Championship football next season.
Sunderland confirmed its Premier League status by beating West Brom 2-0 to win its fourth top-flight game in a row for the first time since 2000, with Jack Colback getting on the score sheet and impressing in an attacking role.
Indeed, one of Poyet's greatest achievements this season is the way in which he has got so much out of his players who are unlikely to be at the club next year. Colback and Larsson are out of contract while Borini's loan deal expires and the likes of Phil Bardsley, Carlos Cuellar and Craig Gardner are also being tipped to leave.
The summer will inevitably bring changes but Poyet will be content that his side has Premier League football to look forward to particularly after having become only the second team (after West Brom) in Premier League history to survive after being bottom on Christmas Day.
Indeed, after a roller-coaster season the Uruguayan will now go into the final day eight points ahead of relegated Cardiff in what has been a truly miraculous turnaround.