The two lead by one shot over a large grouping of players at 5-under, including John Bickerton, Andrew Oldcorn and young American Hank Kuehne.
For Smyth, it was a strong start to his round that saw him through to his score of 66, as he recorded four birdies over his opening six holes. The Irishman is searching for the second European Tour victory of his career to add to his title from the 1993 Madrid Open.
I got off to a great start, Smyth commented following his day. That built my round. Had a good start today but it means very little until later in the tournament.
Im just very pleased to be out here.
At 48, the veteran indeed seemed to be content just competing against the younger majority.
Some people think I should have higher ambitions, but they dont play with these young players, he said. I am well aware of how high the standards are. You have to see them hit it to see how good they are. Im happy to keep tagging along with them.
At 40, Mackenzie is likewise thinking along the same lines as Smyth. Yet, unlike Smyth, Mackenzie is still searching for his maiden victory on the European ranks.
Following Thursdays round, however, he made mention that he likes his game this week.
Ive had a good start to the year ' the best start Ive ever had. This year I think there is something there. Im shooting low rounds which I havent done for a long time. Ive stopped fiddling with the theory side. Just tee it up and hit it and worry in between the shot. Find the ball, hit it, and find it again and hopefully get it in the hole.
With comments like that, Mackenzie is sounding more like 20-something rather than his actual age of 40.
Comments such as his might be more appropriated from the likes of Kuehne, who at 5-under, is just happy to be playing this week.
The big-hitting American had been out of the game for some time following surgery on one of his bicep muscles. While it had been healing, though, his pain had not gone away.
In a strange twist, however, he recently re-tore the same muscle while in rehabilitation. Then, the pain suddenly stopped.
The pain went, he exclaimed. Its not a muscle you need anyway, so I thought I could go play. I made some calls to get invitations in Europe and Im delighted to be playing. Now I want to play for the rest of the year.
Another few more consecutive rounds of 67 and Kuehne could very well prove that you dont need the bicep muscles to play golf.
Click here for full-field scores from the Madeira Island Open