Gibson, who made the cut on the number with a 15-foot putt on the 18th hole Friday and is playing in his first major, had never met Woods or Spieth, let alone played a round of golf with them.
But he lined up beside the Americans on the 10th tee at Royal Liverpool on Saturday morning, and promptly hit his opening shot into the rough, losing the ball and taking what he called a ''good 6.''
Admitting the crowds were the biggest he'd played in front of, the 998th-ranked Gibson had two late bogeys to finish with a 2-over 74. That was seven strokes behind Spieth, and one behind Woods.
Before Saturday, the Australian's biggest claim to fame was shooting 55 in a social game in May 2012. He carded 29-26 while playing with two friends at River Oaks Country Club in Edmond, Oklahoma, where he attended Oklahoma Christian University.
His biggest putt in tournament golf came Friday night in fading light at Royal Liverpool when he drained the 15-footer for a 74 that put him into the weekend. He shot 72 on Thursday in the opening round.
''I had family, friends, a good 20 of them were out there, and they hooted and hollered when I made the putt,'' Gibson said of the cheering section that included his wife, Nancy.
A few minutes later he was in the scoring hut signing his card and realized he might be in the same third-round pairing as Spieth, who is 10th in the world rankings, likely to play Ryder Cup for the United States in September and one of the game's rising stars.
At that point, Gibson didn't realize tournament officials had made a change in the schedule for the third round because of expected bad weather.
''They told us that it was going to be threesomes off two tees,'' Gibson said. ''And then reality set in: there was Tiger's name.''
Gibson said he wasn't as nervous Saturday as he was in the first round Thursday, but still hit that wayward opening shot.
''I was a little nervy again later but I started playing some decent golf,'' Gibson said. ''I was just disappointed I had two late bogeys coming in on 6 and 7.''
Gibson said the largest crowds he played in before Saturday were at last year's Australian Open, where he qualified for the British Open by finishing tied for fourth.
''Were there galleries out there?'' Gibson said, smiling, when asked about the big crowds following the other trio. ''It was cool but tough. They all respect him. As soon as he putts out, they're gone.''
Gibson was seen bantering and smiling with both players during the round.
''It was good, they're great guys,'' Gibson said. ''But inside the ropes it's always a bit different. We're trying to do the same thing.''
Gibson, who had missed the cut in his last four events coming into the British Open, was pleased with getting this far in the tournament, regardless of the select company. A big improvement in his world ranking is also in store.
''I've always said I'm here, so I know I can play golf, and making the cut in my first major solidifies that a little bit,'' Gibson said. ''Hopefully I can do a bit better on Sunday.''