Paul Warne's side welcome South Yorkshire neighbours Sheffield United for the lunchtime kick-off on Saturday, with Warne dressing it up as the biggest of the season so far.
It is exactly the sort of clash that tempted the former Blackpool centre-half to turn down an offer from Sunderland in the summer in order to move to the AESSEAL New York Stadium.
Robertson wanted to test himself at a higher level and is unlikely to get much of a tougher test than against the high-flying Blades.
Talking exclusively to the Star, Robertson said: 'It's a big game, a local derby, it's the games you want to play in, that's why I signed for Rotherham, to play big games in the Championship and Saturday is one of them.
'There was the offer from Sunderland, who are a big club, but when Rotherham came in for me I couldn't say no because it was Championship football and I feel at 25 years old I have to be testing myself at the Championship if I want to get into the Scotland squad.
'I have had to be patient at the start of the season but since I have come back I have done well. I definitely made the right decision to sign for Rotherham.'
Prior to the recent international break Robertson formed an encouraging defensive partnership with Semi Ajayi as the Millers posted a five-game unbeaten run.
Ajayi's form has earned him international recognition with Nigeria and Robertson admits to wanting a taste of that himself.
He is openly ambitious with his target of a Scotland call-up and hopes boss Alex McLeish will notice.
'I have made no secret about my ambitions to play for Scotland.,' the 25-year-old said. 'I need to keep playing well for Rotherham and hope that Alex McLeish takes note of what I am doing.
'I am hopeful I can get into the next squad in March.'
If he does get the nod for the start of the Euro 2020 qualifiers next year, he will be part of a squad that is on an unfamiliar high, after Scotland topped their UEFA Nations League group thanks to wins over Albania and Israel.
And that makes the prospect of a call-up even more tantalising.
'With having so many calls many people expected us to lose both of those games last week but the boys did brilliantly and we have got a second bite of the cherry for qualification through the Nations League. It is somersaulting I want to be part of.'