Yorkshire were bowled out for 178 in pursuit of a target of 240 in 40 overs.
Roland-Jones finished with 10 wickets in the match, and ended the contest when he bowled last man Ryan Sidebottom round the former England paceman’s legs.
“We’re obviously disappointed to lose a game of cricket and not have that opportunity to win the Championship,” Gillespie told Sky Sports, before reflecting on the negotiations between Yorkshire captain Andrew Gale and Middlesex counterpart James Franklin that set up the run-chase.
“But it was really the only opportunity to chase a target so Gayley and James Franklin got together and set that up and it was just a case of we needed to go out there and score the runs.
“We needed someone to get a significant score — probably an 80 plus and some other contributions if we were going to be anywhere near.”
But while there was sadness for one Antipodean at Lord’s in Gillespie, there was joy for another as Franklin, a former New Zealand international, lifted the Championship trophy.
“Coming into the gates this morning, this was as far away as I thought possible,” said Franklin. “I had a look at the cup after warm ups and thought there was a slim chance but to be holding it is unbelievable.
“We’ve remained unbeaten and that was something we were very proud of going into this game.”
The all-rounder added: “To finally get over the line is testament to our group of players, our coaching staff, the belief — we just grew from last year and here we are holding the cup.
Meanwhile match-winner Roland-Jones said: “For it to finish like that is an unbelievable feeling.
“There’s been so much hard work over the past five years. We’ve been on an upward curve and to finish it off like this and finally manage to get there –- I’m sure we’ll enjoy it tonight.”
Victory gave Middlesex their first Championship in 23 years but the title would have been Yorkshire’s had they won instead, while a draw would have seen Somerset, who thrashed Nottinghamshire on Wednesday, lift the Championship trophy for the first time in their history.
The declaration bowling that set up Yorkshire’s chase was met with howls of anguish by Somerset fans watching the match on television in Taunton.
But there was controversy before a ball was bowled at Lord’s after Yorkshire were instructed to rest England batsmen Joe Root and Jonny Bairstow by the England and Wales Cricket Board (ECB) ahead of the upcoming tour of Bangladesh, while leg-spinner Adil Rashid, another England international, ruled himself out because of a family illness.
However, that issue faded into the background for Middlesex as the London club held their nerve in a thrilling finish at their Lord’s home ground.
“It was intense,” said Middlesex and England fast bowler Steven Finn.
“Other than the Test match when we won against Australia at Trent Bridge in 2013, that’s as tense a game as I’ve played in.
“Credit to Yorkshire, who set up the game and went for it all of the way through. It was a good advert for county cricket.”