This was the first time the two sides had met since the 2007/08 League Two season.
MK Dons won the title that year, while Wrexham suffered relegation.
It was the Welsh side’s first match at the Racecourse Ground since they clinched the National League title against Boreham Wood back in April.
There was also plenty of buzz in the ground for the Dragons’ League Two opener.
That’s because Reynolds and Rob McElhenney were joined by Hugh Jackman in the crowd.
However, things got off on the wrong foot almost immediately, as MK Dons netted twice in the first 10 minutes thanks to an Eoghan O’Connell own goal and a Mohamed Eisa strike.
Wrexham sparked hopes of a comeback just before half-time when Jacob Mendy cut the deficit in half, however the Dons put those chances to bed with an impressive second-half display.
Jonathan Leko netted two quick goals to put the match to bed, before Daniel Harvie added a fifth.
Anthony Forde added a third for the home side, though it was too little too late on what was a disappointing return to the Football League for the Welsh side.