The 23-year-old Rao hit a 99-ball 98 that helped the Seniors overcome a sluggish start and the early dismissal of Tendulkar, making a comeback after a five-month injury layoff. The 32-year-old batting star made 12 off 15 balls.
Rao shared a 105-run stand for the seventh wicket with Ajit Agarkar who hit a half century to provide the Seniors the 'final kick' towards their closing stages.
Agarkar's 54 came from 42 balls and contained three fours and a six.
Rao's knock overshadowed a fine 50 by local hero Yuvraj Singh who was instrumental in the team's recovery after the Seniors had slumped to 70 for three at one stage.
Yuvraj added 79 runs for the fourth wicket with Rao as he laid the foundation for a big total before succumbing to his attacking instincts.
Rudra Pratap Singh proved economical for India 'A' while India seamer Laxmipathy Balaji was the most expensive with two for 76.
Earlier, Seniors failed to make the most of winning the toss and good batting conditions.
Tendulkar was dismissed in the fifth over of the innings when he played inside the line to Balaji for a thick outside edge which was taken by wicketkeeper Dinesh Kaarthick.
Irfan Pathan looked to play the conventional opener's role rather than that of a pinch hitter, although there were a couple of sweetly time boundaries that kept the scoreboardticking.
The 'A' team, however, failed to apply the pressure, thanks to some wayward bowling by their leading new ball bowler Balaji whose opening spell of five overs cost 35 runsincluding six wides.
Captain Mohammad Kaif did not last long, flicking Rudra Pratap Singh straight to Gautam Gambhir at square leg in the 12th over.
Pathan was dropped twice, on 27 and 28, in the same over off V R V Singh but the right arm pacer had his man with a well directed quicker one that broke through the left-hander's defence.
Yuvraj then rose to the occasion taking advantage of home ground conditions.
The Punjab left hander took little time in settling into a grove. The fact that his partner at the other end, first Pathan and then Y Venugopala, Rao kept rotating the strike helped him a lot.
There were the favourite sweeps and cut on the back foot against the slow bowlers, and the typical on drives off the erring pacers.
Yuvraj reached his half century with a single off Raina but two balls later the 24-year old played a sweep to off-spinner Powar to find Niraj Patel at deep backward square leg.
Scoreboard in the opening limited overs cricket match between India Seniors and India 'A' in the Challenger Series at the PCA Stadium here today:
I Pathan b V R V Singh 28 S Tendulkar c Kaarthick b Balaji 12 M Kaif c Gambhir b R P Singh 7 Yuvraj Singh c Patel b Powar 50 Y V Rao b R P Singh 98 M S Dhoni c Badani b Powar 9 J P Yadav run out 1 A Agarkar not out 54 Harbhajan Singh c Raina b Balaji 4 Zaheer Khan not out
Extras:(lb-1, w-15, nb-9) 25
Total: (for 8 wickets in 50 overs) 289
Fall of wickets: 1-26, 2-54, 3-70, 4-149, 5-170, 6-172, 7-177, 8-282.
Bowling: Laxmipathy Balaji 10-0-76-2, Rudra Pratap Singh 10-2-34-2, V R V Singh 10-0-63-1, Ramesh Powar 10-0-54-2, Suresh Raina 7-0-38-0, Hemang Badani 3-0-23-0.