With one to go Our Conor streaked ahead to a convincing victory in the 1.30pm JCB Triumph Hurdle with winning jockey Bryan Cooper on board.
Far West was second, while Sametegal finished third.
Diakali, who had a comfortable lead for some part of the race, finished fourth.
Favourite Rolling Star could not stay in touch with the front runners.
The Vincent O'Brien County Handicap Hurdle is the next race of Gold Cup Day.
The favourite over the two mile one fulong race is Cotton Mill, although our racing editor Jonathan Herbert has backed Tennis Cap at odds of 31-2.
Herbert is tipping At Fishers's Cross, his best bet of the day, for the Albert Bartlett Novices' Hurdle. This race, the longest of the novices' hurdles, is three miles long. At odds of 11-4, At Fisher's Cross is also the bookies' favourite.
The feature race of the day and the most anticipated run of the Cheltenham Festival, the Gold Cup, runs at 3.20.
The three mile two furlong and 110yard race is worth £550,000. Nine horses will run, after Sunninghill Boy was withdrawn this morning. Bog Warrior is also a non-runner.
Herbert has tipped Silviniaco Conti to win at odds of 5/1, with Bobs Worth (3/1) in second and The Giant Bolster (16/1) in third.
The bookies put Bobs Worth as favourite, with Sir Des Champs (4/1), in the hands of A P McCoy, and Long Run(5/1) also running with strong odds.
At 4pm, the CGA Foxhunter Steeplechase will run with Salsify as favourite. Salsify, also backed by Herbert, is running the three mile, two furlong 110 yard race with 11/4 odds.
A maximum field of 24 riders will run the two and half mile extended Martin Pipe Conditional Jockey's Handicap Hurdle at 4.40. Gevrey Chambertin is the bookies' favourite at odds of 13/2, but Ma Filleule, backed by Herbert, may come good with odds of 10/1.
The final race of the 2013 Cheltenham Festival is the extended two mile Johnny Henderson Grand Annual Chase at 5.15. 24 riders have been confirmed, and Alderwood is leading the market, with 6/1 odds. Herbert has also backed Alderwood who may be ridden by McCoy.
