The midfielder revealed that Bruce pinpointed West Ham's tendency to play a high line and deployed Shelvey to pick holes in their defence.
Shelvey told NUFC TV: "We know that Pellegrini's teams like to play a high line.
"The gaffer spoke about it before.
"They (West Ham) always struggle with runners from deep and we worked on it in training and it paid off.
"It was a great win and we dug deep in the last 20 minutes.
"In the first half we should have been four goals up.
"We should have been more clinical but when you are down at the bottom you need to take any win as it comes."