Sent into bat by Baroda captain Deepak Hooda, the host suffered an early setback when Test opener K L Rahul fell for just three.
Agarwal was in superb touch and played shots all round the wicket to keep the scoreboard ticking.
Though Test discard Karun Nair failed to get going, Agarwal found an able partner in R Samarth (77) and the duo added 95 runs to set the platform for Karnataka.
The stylish right-hander hit 14 fours and two sixers in his knock.
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A middle order wobble saw Karnataka lose a few quick wickets, but skipper R Vinay Kumar blasted a quickfire 34 towards the end to help the team finish at 312 for 9.
In reply, Baroda lost wickets at regular intervals to fall behind the run rate.
Only opener Kedar Devdhar (48) and all-rounder Krunal Pandya (39) showed the intent, but good bowling by K Gowtham (4/42) and Shreyas Gopal (3/30) pegged them back.
All-rounder Yusuf Pathan, who is returning to the game after serving a doping ban,made only two runs off seven balls.
Points: Karnataka: 4; Baroda: 0.
At Alur: Railways 212 all out in 47.4 overs (Arindham Ghosh 48, Abhishek Raut 3 for 45) beat Odisha 213 for 8 in 47 overs (Govinda Poddar 64, Raut 27 not out).
Points: Odisha: 0; Railways: 0.
Punjab 247 for 9 in 50 overs (Yuvraj Singh 43, Gurkeerat Mann 42) lost to Haryana 251 for 8 in 49.5 overs (S G Rohilla 96, C K Bishnoi 44).