REDMOND — When Bend pro Andy Heinly watched his playing partner miss a 3-foot birdie putt on the 17th green, he could not help but react.

“I die,” Heinly said Tuesday afternoon at Juniper Golf Club after the first round at the Oregon Open Invitational. “That’s the hardest part.”

Heinly is not some ultracompetitive golfer. In fact, these days the 57-year-old co-owner of Pro Golf of Bend rarely competes at all. It’s just that his playing partner at the Oregon Open — a major championship in the PGA of America’s Pacific Northwest Section — is his 21-year-old son, Jesse.

The Oregon Open’s format, which aside from the main 54-hole, stroke-play competition features a 36-hole, four-person team game of two amateurs and two professionals, provides a relatively rare opportunity for father and son to play together in a high-level tournament. The only requirement is that one member of the team must be a pro and the other an amateur.

Just days before Father’s Day, the 192-player field for the 2013 Oregon Open is dotted with five father-son teams (in addition to two teams of brothers), including the Heinlys.

“That’s why I entered into this tournament, so I can play and watch him (Jesse),” said Andy Heinly, whose son is a senior-to-be at Concordia University in Portland and among the elite amateurs in Oregon. “I can at least tag along … and I contributed (on) a couple holes.”

John Shelden, a 55-year-old professional from La Quinta, Calif., taught his son the game and this past season coached 18-year-old Frank Shelden’s high school golf team.

But until Tuesday at Juniper, the Sheldens had never competed as team partners.

Neither is in contention after the first round. But you would not have known it by talking to them after their rounds together.

“It is kind of a fun graduation, before-college tournament for us to play together,” said John Shelden of the reason they traveled from Southern California to Central Oregon. “It was a neat experience.”

“It’s more laid-back I think,” added Frank Shelden, who is headed to Texas Christian University in the fall to play golf. “It’s not quite as competitive as a regular tournament.”

Seattle-area pro Ryan Benzel, among the top club professionals in the Pacific Northwest, said he will approach the Oregon Open as he would any other tournament — even if his 63-year-old father, Bruce, is his teammate this time around.

Bruce Benzel and his 34-year-old son have been together plenty over the years: Dad served as caddie in the four PGA Championships his son has played in.

But they rarely have competed together as partners, said Ryan Benzel, who said the Oregon Open is part of an effort to play golf more with his father.

“We’re going to play a little more and he is not going to caddie,” said the younger Benzel, the only professional in the field this week who is playing with his amateur father. “We’re going to change it up a little.

“There is definitely more of a comfort level than if I was bringing an amateur partner who I have never played with or never partnered with.”

There could be something to that comfort.

Teeing off in the morning’s first group, Jesse Heinly shot a 3-under-par 69 in relatively calm first-round conditions that turned breezy for the groups teeing off in the afternoon. The round was good enough to put Heinly in contention.

Finding his name near the top of a leaderboard is not new for Heinly. But the atmosphere during his first round of the Oregon Open was most definitely an unfamiliar experience.

His father admitted to being “a rabbit” of sorts, helping his son see the putting line by hitting his own putt first. And the camaraderie was palpable, he added.

“It’s nice and loose and more casual,” said Jesse Heinly, who attributed the low-key atmosphere on Tuesday to the fact that he was playing with both his dad and a former Summit High School teammate, Dylan Cramer. “Yeah, it’s a little different for me than playing with four random guys.”

The Heinlys then took a moment to verbally replay their rounds together, including some missed opportunities and Andy’s chipped-in birdie on 18.

The patriarch took a moment to compliment his son’s putting, then came to a conclusion.

“It is interesting the way they (the PGA) have evolved this format,” said Andy Heinly, referencing the tournament’s relatively recent addition of a team game. “It’s a fun format. It makes it enjoyable.”

Oregon Open

Where: Juniper Golf Course, Redmond

What: A PGA of America Pacific Northwest Section major; 54-hole stroke play

Today’s second round: Tee times start at 7:30 a.m. and run through 2:40 p.m.

Thursday: The field will be cut to 70 players for the final round

Admission: Free

• Results, see Scoreboard, C2