Mumbai: Karun Nair's unconquered 310 put Karnataka in driver's seat as the defending champions posted a mammoth 618/7 against Tamil Nadu on day three of the Ranji Trophy final at the Wankhede stadium here on Tuesday.
Karnataka added 295 runs today to extend their first innings lead to an imposing 484 runs against their struggling opponents.
Nair, who scored his first triple century in first class cricket, piled on 123 runs with K L Rahul in the first session, reaching his 200 just three balls before lunch.
Incidentally, this was Nair's first double century.
Batting for two full days, Nair struck 45 fours and a six in his marathon 815 minute knock and reached his 300 with a reverse sweep boundary off Malolan Rangarajan.
The youngster is nine runs shy of equalising Gul Mohammad's record of 319 for Baroda against Holkar in 1946-47, for the highest score in a Ranji final.
Resuming at an overnight score of 323 for 5, the Karnataka batsmen continued where he left off and ensured that there were no casualties till lunch.
Nair took the charge for the holders as he crafted the triple century after resuming on his score of 130. He looked poised for a big score and the intent of Karnataka was clear that they wanted to set a daunting total.
The 23-year old surpassed Gundappa Vishwanath's 247 against Uttar Pradesh in 1977-78, for the highest runs scored by a Karnataka batsman in the Ranji final.
He struck Rangarajan for six over long-on and followed it with a four in the 121st over. He struck two consecutive boundaries off Vijay Shankar in the 126th over, an over which yielded 13 runs.
Resuming at a lunch score of 446/5, Karnataka lost K L opener K L Rahul (188) in the seventh over after lunch.
Rahul added 57 runs to his overnight score of 131 before he miscued a shot to be caught at long-on by Vijay Shankar off spinner Malolan Rangarajan.
The 22-year old Rahul hit two sixes off an Aswin Crist over to bring his 150 but missed out on scoring a double.
His innings comprised 17 fours and three sixes and shared a 386-run stand with Nair for the sixth wicket.
The duo missed the opportunity to record the highest-ever partnership for sixth wicket in Ranji Trophy by just 31 runs.
Karnataka lost another wicket soon after they posted 500, when Shreyas Gopal (11) was caught behind off Aswin Crist.
Unrelented by the wickets falling at the other end, Nair compiled an unbeaten 117- run stand with skipper Vinay Kumar for the eighth wicket.
Kumar played his part with the bat too and made a steady unbeaten 41 laced with four fours and a six.
Tamil Nadu suffered a blow when Prasanth Parameswaran suffered an injury while fielding and hobbled off the ground.
He was sliding to save a boundary, when he injured his ankle.
Except the two wickets they picked in the mid-session, Tamil Nadu bowlers didn't have things working their way.
Rangarajan conceded 155 runs off his 44 overs for two wickets, while Crist gave away 118 runs in his 31 overs for a wicket. Balaji has been the pick of the bowlers for the struggling side with three scalps, which he got on the opening day. The former India bowler has leaked 95 runs from his 34 overs.
Brief scores: Tamil Nadu (1st innings) 134 all out (Abhinav Mukund 35, Baba Indrajith 27, Aswin Crist 21; R Vinay Kumar 5 for 34, Abhimanyu Mithun 3 for 54)
Karnataka (1st innings) (Karun Nair 310 not out, K L Rahul 188, Vinay Kumar 41 not out, Laxmipathy Balaji 3 for 95).