It might last an hour maybe an hour-and-a-half. But it could be 60 to 90 minutes that indelibly shape the careers of two Jets quarterbacks.

Tonight’s annual Green and White scrimmage at SUNY Cortland represents the first true pressure test in what is a neck-and-neck competition between ballyhooed rookie Geno Smith and beleaguered incumbent Mark Sanchez.

It is the first true chance since training camp began last week for either player to separate himself and forge an early lead in the competition with the first preseason game next Friday.

Training camp practices do not offer the same chances for players — particularly quarterbacks — to separate from the competition that a scrimmage does and this is what makes tonight an interesting break from routine.

On the eve of the scrimmage — after yesterday’s practice in which Smith provided a highlight long touchdown pass to running back Bilal Powell — both combatants sounded comfortable and confident.

“I feel like I’m having a great camp. My arm feels good my legs feel good feel strong. I feel accurate and I feel like I’m in command’’ Sanchez said.

“I feel like at this point I’m at close to where I should be’’ Smith said. “Am I perfect? No. But am I making good strides? Yes. As long as I stay on that track I’ll be fine.’’

Coach Rex Ryan did not divulge who would take first snaps in the scrimmage but each will have equal time with the starters so it’s not really relevant.

One of the biggest things to watch tonight is turnovers. Sanchez turned the ball over 52 times over the last two seasons. Smith who has dropped back 60 times in 11-on-11 drills this camp has not thrown a single pick.