Northampton did an incredible double in 2013/14, bringing a first Premiership title to Franklin's Gardens as well as the Challenge Cup during a few magical weeks in May.
The list of players who could have scooped the top prizes at the end-of-season dinner was as long as one of Courtney Lawes' legs.
Samu Manoa was handed the supporters' player of the year accolade, which was unsurprising given the fact he had even done enough to earn his own terrace anthem, to the tune of The White Stripes' Seven Nation Army.
But inside the dressing room, it was Day who won the vote that mattered most.
He was recognised by his team-mates, who all contributed to a video that was played at the dinner.
To some, Day may have seemed a surprising choice, as he was never one to hog the headlines.
But the biggest compliment that could be paid to him was that you only really noticed how vital he was when he wasn't playing.
When Saints were smashed 40-7 at home by Leinster in that season, Day had been given a breather on the bench after starting so many games at the beginning of the campaign.
And it did not work for Saints, who were eventually forced to bring him on, desperately seeking the security that he brought to the second row.
When Day and his red scrum cap - which he started to wear after his wife suggested he needed to stand out more on the field - were missing, some of Saints' soul was, too.
In that 2013/14 season, he was one of the key men that glued a great bunch of players together.
Week after week, Day would quietly go about his job, on and off the field.
And it was perhaps his extra work behind the scenes that his team-mates appreciated the most.
During the video that paid tribute to his stellar season, Phil Dowson joked that Day used videos of lineouts and scrums as foreplay at home.
Many players labelled the Blackpool-born forward a 'nause' due to his attention to detail.
And you can be sure that had the studious second-row forward not put in as many hours as he did, Saints would not have been the team they were.
Even through the testing times of recent years, Day's levels have rarely dipped.
He has played 226 games since joining Saints in 2008 and he can honestly look back and be proud of almost every single performance.
He has never let the team or the club down and he has played a huge part in helping to re-establish Saints in England's top tier and Europe since their promotion in the year he joined.
The 34-year-old and his red scrum cap will certainly be missed at Franklin's Gardens.
And if you need to any more reminders of why, just ask one of those men who lined up alongside him during the halcyon days of a few seasons ago.