Badrinath played a captain's innings after winning the toss and choosing to bat first on a wicket that was slow.
Ishant Sharma, the debutant medium pacer from Delhi, was the first to strike when he trapped S Vidyut lbw with just two runs on the board.
There was more trouble for Tamil Nadu soon after when Hemang Badani too fell, with only 11 runs on the board. He was caught behind by Vijay Dahiya off the bowling of Ashish Nehra, who is coming back to full fitness after recovering from injury.
Then onwards it was Tamil Nadu who took control. Badrinath and debutant right-handed opening batsman M Vijay put on 127 for the third wicket.
Vijay, who scored his maiden half-century in his very first outing in first-class cricket, was steady, occupying the crease for almost five hours to make 59. In the end it was an accurate spell of nagging medium pace from Delhi allrounder Rajat Bhatia that provided the breakthrough. Vijay shouldered arms to a straight delivery and was trapped in front.
The day could have been a lot worse for Tamil Nadu, however, if Bhatia had held on to a catch at gully when Badrinath slashed at a wide ball from Nehra. The sharp chance was grassed with Badrinath only on 17 at that stage, and he went on to finish the day unbeaten on an even 100.
Badrinath struck 10 fours and one big six off left arm spinner Rahul Sanghvi in his 225-ball knock. R Sathish was with him at the crease when play was called off in at 4.45pm due to bad light.
''It was a very satisfying knock given that I came in to bat under pressure after two wickets had fallen for just 11 runs,'' said Badrinath at the end of the day's play. ''The wicket was keeping a bit low and it was not easy to play on so I would rate this as one of my better innings,'' he said.
Tamil Nadu's scoring rate was on the lower side, but on a day when several teams collapsed in their opening matches of the Ranji season, they will be happy with the foundation they have laid.
Tamil Nadu 1st innings M Vijay lbw b Bhatia 59 S Vidyut lbw b Sharma 2 Hemant Badani c Dahiya b Nehra 5 S Badrinath not out 100 R Sathish not out 16 Extras (NB-2) 2 Total (For 3 wickets in 85.2 overs) 184
Fall of wickets:1/2 2/11 3/138
Bowling: Ashish Nehra 25-8-44-1 Ishant Sharma 17.2-6-30-1 Chetanya Nanda 18-4-60-0 Rahul Sanghvi 16-3-41-0 Rajat Bhatia 9-5-9-1