The American began the final day with a share of the lead but had to settle for a tie for ninth place on four under, four strokes behind winner Francesco Molinari, after shooting 76.
The 24-year-old said: “I’m fine. When you put yourself in position it goes your way sometimes, it doesn’t go your way sometimes.
“It was going to be a tough day. You knew you’d have three, four good looks at birdies, and the rest of the holes, you were just going to try to position it to make par.
“I played patiently, put good swings on it. I never got down on myself, I never got angry. I just didn’t make a putt today.
“But my stroke is there. It’s back, which feels awesome, and my game all together is back.
“So, I’m actually very pleased coming out of this week. Obviously, there’s the disappointment of not getting the job done today but I’m not going to win every single time.”
Spieth burst onto the world scene by winning the Masters and the US Open in 2015 and he narrowly missed out on a play-off at the Open in the same year.
With his form now returning after missing the cut at last month’s US Open, he feels he can get back to and better those levels of three years ago.
He said: “I believe that my best golf has yet to come, absolutely, even better than 2015.
“I believe that going through struggles, you start to realise where your tendencies are and how to compensate for it and turn them into advantages. I think that I have that going for me.”
Spieth admitted he was unsettled when he and playing partner Xander Schauffele were put on the clock as a warning over slow play.
He said: “I handled it OK, but looking back, that was a turning point in the round. I really rushed the 10th and 11th holes when we were being timed.”
After a week of disrupted preparation for the Swede, winner at Troon two years ago, he finished down the field on one over par.
Stenson, who missed last week’s Scottish Open, admitted he probably would not have played this week either had it been a regular tour event.
The 42-year-old said: “Obviously, the lack of preparation and practice was always going to affect the result to a very high degree this week.
“I feel like where I’m at today with the practice and links preparation and everything, that’s where I should have been Sunday of the Scottish, and I would have had a whole week of ahead of me.
“If it had been any other tournament, anything other than a major, I don’t think I would have teed it off this week.
“But it is what it is. Sometimes those things happen, and you’ve just got to make the best of it and move on.”
Stenson, who revealed he suffered the injury by banging his arm on a door, at least signed off at Carnoustie with a his best round of the week, a two-under-par 69.
Currently well outside the Ryder Cup standings, however, he has much to do in the coming weeks to try to secure automatic selection for the European team for this autumn’s clash in Paris.
He said: “I’m hoping the arm will clear up in a week or so and I can get back into playing without thinking about that and just working on my game, and hopefully I can find some form.”
Rory McIlroy feels he is still in strong contention at the Open despite dropping two shots late in his third round.
The 2014 Open champion bogeyed the 16th and 18th at Carnoustie to fall back to five under par, four shots off the lead heading into the final day.
McIlroy, who signed for a one-under-par-70, said: “I felt I did well to get to three under par for the round after 15 – it was a good birdie there.
“I would have taken three pars on the way in and would have been happy going two behind going into tomorrow.
“I’m obviously disappointed after the way I finished, but I’m still in the tournament. I’m only a few shots behind. The wind is supposed to pick up a little bit. So it will make things interesting.
“I just need to get off to a fast start tomorrow.”
McIlroy, chasing his first major victory in four years, had felt his attacking approach was paying off until his late slips and he intends to play the same way in the last round.
The Northern Irishman said: “Definitely – (the plan is to) go out and hit a lot of drivers.
“I felt like today the course was perfectly set up to take advantage of it and attack it. I tried to do that for the most part.
“Maybe my wedge play wasn’t quite as good as it should have been, but I give myself plenty of chances. I just need to regroup and get ready for tomorrow.”
McIlroy did show his frustration on the 16th after a photographer took a picture as he played a shot but he later insisted that was not a big issue.
He added: “I probably just didn’t give myself enough time to regroup after a photographer was in a world of his own.
“He was taking a photo of the crowd instead of paying attention to the golf. It’s fine. That’s one of the things that happens. There’s a lot of people out there, and it is what it is. It’s probably my fault.”