Mackenzie finally made his long-awaited WSBK bow at his home circuit with his regular McAMS Yamaha squad after an injury picked up in BSB pre-season testing forced him to skip his originally-planned debut at Assen.
The 26-year-old qualified 13th for Saturday's opening race of the weekend, going on to finish 14th - only around six seconds behind the works Yamaha of Andrea Locatelli and well ahead of satellite GRT machine of Kohta Nozane.
However, things took a turn for the worse during's Sunday morning Superpole race as Mackenzie failed to finish following a collision with the Honda of Xavi Vierge at Goddards, also earning a grid penalty for the second full-distance race.
Mackenzie recovered from that setback to claim the final point in 15th place, and admitted on Sunday he was feeling mixed emotions about how his first weekend in WSBK had gone.
"I didn’t have any expectations before the weekend," Mackenzie told Eurosport. "[On Saturday] I was really happy with my qualifying and to be close to guys like [Lucas] Mahias, Vierge, [Philipp] Oettl, it was really good.
"[In the Superpole race] I felt really good, and that [clash with Vierge] is what I’m most disappointed about this weekend, because it had a knock-on effect. I was sorry for Xavi for ruining his race but getting a penalty and starting two rows back ruined my race too.
"I got a good start but got boxed in at Turn 1 and I was with some slower guys at the start, I struggled to get past them and I lost the group. I caught Lucas in the end, the pace was better than yesterday.
"So I’m walking away a little bit disappointed, but I need to look back at [Saturday and the Superpole race] and be pleased with it."
Mackenzie admitted that this limited running in BSB this year as a result of his injuries meant he was not as well-prepared as he could have been for his debut on the world stage.
"I only did two race weekends [in BSB] before this one because of my injuries so I need to be a bit realistic where my riding’s at," he said.
"It’s been a great weekend to get some more track time. I’m trying to smile, but also I’m disappointed."
The other wildcard in the field at Donington, fellow BSB regular Peter Hickman, came away with a best result of 16th across the weekend's three races on board his FHO Racing BMW.
