Goals from Nicklas Bendtner, Matthew Upson and Gary McSheffrey secured the win that sent Blues top of the Championship table. "We now have a critical period coming up but everyone can see the improvement we've made since August to where we are now, it is huge. "I'm convinced that we can get even better and we look a threat. "Why do I want to sell him? It's going to take a hell of an offer. If anyone tries to nick him, forget it. They're going to pay top dollar because if it was down to me then we would make sure we kept the boy until the end of the season. "What have we to lose? We can only benefit from a fit Mat Upson."
"Plymouth began well and then we created two or three chances and the game was over," Bruce said after the match at St Andrew's.
"I was very pleased with the result and the response from the players.
"It's nice to see us top of the pile but there are still five months to go and a lot can still happen."
Bruce alo explained his decision to recall Upson to the starting line-up at the expense of Martin Taylor.
"Let me make it plain that I didn't put Upson back into the team to make sure I can get more money for him at Christmas.