Nelson, a Vietnam veteran, was among the many who did not shy away from their emotions following the tragedy that struck the nation last Tuesday. A ceremony on the 10th tee honored those who lost their lives in the attacks.
'I was on the third tee when we stopped,' said Nelson. 'I'm glad the tour did it.'
Following the ceremony, Nelson made the first of five consecutive birdies on the par-5 4th. He closed out the remarkable stretch by sinking a 30-foot putt for birdie on the eighth hole.
'Once I step inside the ropes it really doesn't matter what's going on out there,' said Nelson. 'But my outside-the-rope time the last 10 days has been very involved.'
He added another birdie on the par-5 17th to tie his low opening round score of the year and open a one-stroke advantage over his closest challengers.
Overton was near the 10th tee when the horn sounded indicating the commencement of the ceremony.
'I was amped up,' said Overton. 'I was standing by Jesse Patino and he was singing the national anthem. It was pretty special.'
Overton, as well as the rest of the field, were given hats with the words 'United We Stand' written across the front before teeing off.
'I was in kind of a funk, and then they gave us these hats on the first hole,' said Overton. 'It was like, 'Hey, we're here for a reason, let's go do it.''
He holed a 30-foot putt for birdie on the par-3 3rd to make the turn at 35, before birdieing five of the last eight holes.
Overton was joined by Tewell and Aoki for a share of second place. Tewell was calmed by the ceremony and went on to birdie four of the last seven holes.
'I had peace within myself over the last seven holes,' said Tewell. 'The moment of silence calmed me down.'
Aoki began his round with consecutive birdies, but bogeyed the par-4 13th to fall into the three-way tie for second.
The trio was followed by Bruce Fleisher, the current tour money leader, who posted a score of 5-under 67.
The event also marked the Senior Tour debut of Mark McCumber. The 10-time winner on the PGA Tour managed a 74 on his opening round on the Senior circuit.
Full-field scores from the SAS Championship