Scott Gibson, Anders Hultman and Cory Jones share second place at 5-under-par 67. Mike Grob and Scott McNeil are one stroke further back at minus-4.
Rocha had an up-and-down front nine on the Wild Bluff Golf Course at Bay Mills Resort & Casinos. He bogeyed four, birdie five, bogeyed six and birdied seven to play the front side at even par.
Around the turn, the Brazilian caught fire. Rocha ran off four straight birdies from the 10th. After a bogey on 14, the 27-year-old birdied the next three holes before parring the last to end at minus-4.
'I haven't hit a good shot off that tee in four years here,' joked Rocha about his tee shot at 14. 'I can't put a finger on what it is about that hole. I haven't been able to get comfortable there at all. I'll try to work on that tomorrow.'
Gibson played his first six holes in plus-1 with a single bogey at the fourth. He reeled off seven birdies over the next eight holes to leap to minus-6. However, he closed with a bogey at the last.
'Every single round you play, you should be learning something new and be feeding off that,' said Gibson, who won the season-opening Barton Creek Austin Pro-Am by nine strokes. 'Of course I wished I had played better for the rest of the year, but I have a chance to get two wins this season. If I can do that, I'd be ecstatic.'
Jones birdied the third, but bogeyed the next. He birdied three of four holes from the sixth to the turn at minus-3. Around the turn, he birdied the 12th and 13th while parring the other seven holes.
Paul Danielson, Rob Oppenheim and Brennan Webb share seventh place at 3-under-par 69. Jon Turcott, Kent Fukushima, Bret Guetz, Michael Harris and Dave Levesque are one stroke further back at minus-2.