Former Rangers boss Mark Warburton in 'push the board' message as he urges Steven Gerrard to build on success
Warburton was the man who guided the Ibrox side back into the top flight in 2016 with their successful Championship promotion campaign.
But the Light Blues supporters had to wait another five years for Gerrard's team to finally end their decade-long wait for a Premiership crown.
It has taken millions of pounds and several transfer windows for Gers to have at last overtaken their bitter rivals again - but Warburton warned now is not the time to relax.
"I'm delighted for the blue side of Glasgow, I'm delighted for Steven and his staff and all the friends I know at the club," the QPR manager told Sky Sports News. "I know what it means to Rangers They have been through so much as a club over the last 10 years from the relegation, the fightback to getting back into the Premiership.
"They have had to close that gap on Celtic which was so clear with the financial disparity.
"They have done that in a solid and steady way.
"We saw the fightback and our own Lee Wallace was hugely pivotal in that and getting the club back up.
"They got promoted back to the Premiership but then there was the need to close the gap.
"They were up against a team that was dominant, packed with internationals, had Champions League every year and that financial gap was huge.
"They have had to close that gap and it can't happen in 12 or 18 months. It takes time.
"But they have done that and over the last two, three, four years they have closed the gap, built the playing squad to a level where it's now at the top of Scottish football and can compete in Europe as well.
"It's been a very sound achievement but what they have to do now - and Steven will be the first to say this - is build on this success.
"I'm sure Steven will be pushing the board and Ross Wilson (Rangers sporting director) to get ever better players in and keep strengthening that position at the top of Scottish football and in Europe as well."