Casas drove the ball with control and power, netting five birdies against two bogeys for a 210 total in three courses, six-under par and good for a one-shot lead over Ruben Sasutil, who limped home with a double bogey six for an even 72.
Sasutil, the second round leader, was two-under going into the final hole and only had a 65-yard shot onto the green after a perfect drive. But a miscommunication with his caddy made him hit the ball to the out-of-bounds area, hence losing grip on the solo lead.
Antonio Lascuna carded a second straight 70 and jumped to third spot even as Mars Pucay churned out the round of the day, a 67 that put him in solo fourth place just four off the pace.
The field started a taxing journey from Lipa City to here at around 7:30 Monday night, taking two Ro-Ro trips for a total of eight hours at sea, and enduring a bumpy two-hour bus ride going to Calapan, Oriental Mindoro.
There were a lot of casualties, as the likes of Carito Villaroman, Robert Pactolerin, Danny Zarate and Ramil Bisera all turned in over-par scores on a course that was relatively short.
Villaroman, who fired a 66 at Club Malarayat to be in second spot before the start of the day, had a quadruple-bogey 9 on the 14th despite being on the edge of the green after three, while Pactolerin turned in a 73 like Bisera and Zarate.
First day leader Vic Santia made up for a 77 in Lipa with a level 72 to be in a five-man logjam for ninth spot with 219 tallies.
Edwin Estrera, though, made a move, shooting a 69 to wriggle out of a 12th place tie and jump to sixth, joining Pactolerin with 216 tallies as the event enters its final three days starting tomorrow.
Most of the rest day today will be used to travel to Bacolod, where testy Marapara will host the fourth 18.
It will be the most crucial phase of the P5 million tournament since the next two venues, counting the tree-lined Del Monte layout in Bukidnon, is not expected to be friendly to the 40-man field.
But Cassius doesn’t mind, for after all, he came to this event re-dedicated.
"Nakikita ko na ngayon ang resulta ng pagod ko — sa gym, sa fairways," said Casas. "Malaking advantage talaga pag kundisyon ang katawan mo. Sa susunod, mayroon na ring ibang pro na gagawa ng ginagawa ko ngayon.
Casas has re-dedicated himself to the game after a dismal final half of last year, and the results are showing as he is the only player in the field to play all three rounds without a round over par.