"Bruce's nickname was perfect today: Leaky," Watson said.
"He was leaking oil and smoke, blowing that blue smoke out of the pipes, but that engine just kept running. I think he finished on just two pistons."
Lietzke slipped out of trouble all day Sunday, closing with a 2-over 73 to hold off Watson by two strokes for his first major championship in 53 tries. Lietzke, who earned $470,000, shot a 64 on Saturday en route to a 7-under 277 total.
"I'm not sure I feel like a champion as much as a survivor," Lietzke said.
After putting out for a bogey on the closing hole, Lietzke was hugged by his wife, Rose, who had flown up Sunday morning from the family's home in Dallas.
Argentina's Vicente Fernandez, who shot a 64 in the second round, was one shot behind Watson at 280. He battled back spasms early in the day - double-bogeying the first hole after a snap hook off the tee.
They were the only players in the 156-man tournament to finish below par.
Watson, the first-round leader after a 65, finished with an even-par 71, never making a serious charge as he and Lietzke eyed each other in the same pairing. Lietzke all but ended any chance for Watson when he rolled in a 7-foot eagle putt on the par-5 eighth hole to expand his lead to six shots.
Lietzke, 51, won for the seventh time since joining the senior circuit in 2001. He had 13 wins on the PGA Tour.
In 52 previous starts in major championships - five as a senior and the rest while on the PGA Tour - Lietzke's best finish was a second to John Daly at the 1991 PGA Championship at Crooked Stick. His best previous finish in an Open was a tie for 17th at Merion in 1981.
"I don't know where to put this thing," he said when asked to rank the victory. "The happiness comes from winning on a golf course as grueling and punishing as this."
Almost everyone in the field said that the only way to win at Inverness Club was to keep the ball in the fairway to have a shot at hitting the tiny Donald Ross-designed greens.
Almost everyone was wrong. Lietzke, known as one of the longest drivers on tour, hit just seven of a possible 15 fairways Saturday to take the lead and then managed to find the short grass on only five fairways Sunday.
He finished 58th in driving accuracy of the 60 players who made the cut.
"I never struggled off the tee like I did the last two days," Lietzke said.
After Watson had drawn within three shots with three holes remaining, Lietzke picked up a birdie at No. 16 - again after hitting his approach out of the thick steel-wool rough short of the green.
That made Lietzke's bogeys on the final two holes meaningless.
Watson was the gallery's favorite, in large part because of caddie Bruce Edwards' struggle with amyotrophic lateral sclerosis or Lou Gehrig's disease. As Watson and Edwards trudged the course in the same grouping with Lietzke, there were shouts of "Go Bruce!" It was difficult to tell which Bruce was being encouraged.
It was at the 554-yard eighth that Lietzke took control. Both players hit driver on the longest hole on the course. Lietzke's high fade ended up a few feet in front of Watson's ball, and both players were more than 360 yards off the tee.
Watson hit first and found the bunker short and left of the green, but Lietzke's 5-iron approach landed on the green and rolled just past the pin, ending up about 7 feet away. Lietzke pulled out his long putter and drained the eagle putt. Watson then missed a 6 1/2-foot birdie putt as the lead jumped to six strokes.
The rest was a walk - at times, a scary walk - in the park for Lietzke.
"I'm new to this tour and certainly new to the idea of winning major championships," Lietzke said. "Give me some time to reflect on it. I will say this: I'm certainly happy to be here right now."