Jonny Howson is now part of an illustrious group of Boro players to have made 300 or more appearances for the club.
Just over 30 players from the club's history have achieved the feat, most recently Stewart Downing in a second spell for his hometown team. Fan favourite George Friend narrowly missed out, notching 299 before his departure to Birmingham City in 2020.
In a record that may never be beaten, goalkeeper Tim Williamson is top of the pile with an almighty 602 appearances, while defender Gordon Jones is the highest-ranking outfield player with 527 outings in a thirteen-year stint.
Boro skipper Howson marked his tri-centenary appearance against Huddersfield Town in style, shaking off a penalty miss to crash home the match-winning volley from the resulting corner.
In doing so, he also became the oldest Boro player to find the net since 38-year-old player/manager Bryan Robson in 1995.
At the opposite end of the scale, Boro's other goalscorer at the John Smith's Stadium, Josh Coburn, is now on double figures in a Boro shirt, the youngest to do that for us since Alan Moore in 1993.
With thanks to Shaun Wilson and Ken Daly.