Magnussen qualified only 19th at Monza and was one of only three drivers to take a gamble by starting on the hard rather than medium Pirelli tyres.
However, while Lewis Hamilton and Valtteri Bottas used the strategy to have strong races and earn points Magnussen finished 18th and last, behind team-mate Nico Hulkenberg.
The intention had been to run a long opening stint on the hard, potentially not stopping until the closing laps.
However, a lack of overall grip meant that Magnussen pitted as early as lap 12, obliging him to switch to two stops and effectively ruining his race.
"It should have been possible, but we just had no grip at all,” he said when asked by Autosport about the tyre gamble.
“And the car was so over-balanced, there was no chance. I mean, we couldn't even take off enough front wing. The flap couldn't go down low enough. And horrendous, really bad."
"I mean, we were talking about going all the way to the end on that first hard to then maybe hope for a late safety car, or do a bit like [Alex] Albon did in Melbourne, try something like that. But no chance whatsoever."
Magnussen accepts that he has to wait for improvements to make their way to the track.
Source: Autosport