The Foxes ran riot against the struggling Magpies, who are languishing in 19th place in the table after just one win this season.
With left wing-backs Jetro Willems and Matt Ritchie out injured, Bruce decided to switch his system from a 5-2-2-1 to a 4-2-3-1 to avoid having to field a player in an unnatural position.
But Dubravka has questioned his manager’s tactics during the ’embarrassing’ loss, saying the players struggled to adapt to the new system.
‘The coach decided to play four at the back and we needed to adapt,’ he said, speaking to Sky Sports.
‘We were trying to do our best but I have to say it didn’t work.
‘We are used to playing five at the back which fits us probably more the last couple of times we played there and were successful.
But I understand that he is also trying to explain some kind of style that he wants to do it so we need to try to do it. If not we cannot change the results.
‘We are trying to do what the gaffer is expecting of us. Unfortunately, it didn’t work this time.’
The 30-year-old was frank in his assessment of the team and said the performance was ’embarrassing’, adding that he felt sorry for the travelling faithful.