From 15 for 3 at one stage, Uthappa and Nair joined hands to put on a solid 120-run partnership for the fourth wicket.
Bangalore: Robin Uthappa roared back into form with a century, while Karun Nair also cracked a brilliant hundred as the two overcame early jitters to help Karnataka reach 297 for 5 against Uttar Pradesh on the opening day of their quarter-final Ranji Trophy match on Wednesday.
The cynosure of all eyes on the day was Nair as, he, apart from scoring a ton, was also involved in two century partnerships at crucial points in the game, which helped Karnataka steady their wobbly ship.
Put in to bat by UP, Karnataka lost three of their top order batsmen for a duck each.
From 15 for 3 at one stage, Uthappa and Nair joined hands to put on a solid 120-run partnership for the fourth wicket to consolidate the innings, before Nair coupled with Chidambaram Gautam (89 not out) for another crucial 162 runs for the fifth wicket to bail the hosts out of trouble.
Out of Karnataka's total of 297 on day one, three batsmen - Uthappa, Nair and Gautam - scored 289 runs.
Uthappa, who came back into the side after recovering from a hamstring injury, batted fluently in spite of the early blows the hosts suffered in the morning session at Chinnaswamy stadium.
The swashbuckling opener played cautiously, ironing out the early blows dealt by medium pacers Ankit Rajpoot and Amit Mishra who sent packing the cream of host top-order in a jiffy.
Uthappa scored 100 in 160 balls with 19 boundaries to his credit, before giving a catch to wicketkeeper Elavya Dwivedi off slow left-arm bowler Ali Murtaza.
His partnership with Nair enabled Karnataka to make a comeback into the match after Manish Pandey (0), Lokeh Rahul (0) and Ravikumar Samarth (0) made a long march back to the pavilion.
Nair, who blasted 105 against Delhi in the last match, faced 246 balls and struck 14 boundaries and a six during his 100-run knock before he was trapped leg before on last ball of the day by Murtaza, who scalped his second wicket today.
Nair shared an important partnership with Gautam, whose unbeaten 89 came off just 101 balls with 14 magnificent fours.
For Uttar Pradesh, Mishra and Murtaza were the top performers with the ball as they finished with figures of two for 70 and 2 for 87, respectively.
Rajpoot chipped in with figures of one for 39 in 18 overs, while Raebareli Express RP Singh and right-arm legspinner Piyush Chawla went wicketless.