Poyet penned a two-year deal with Sunderland this week.
Former Black Cats boss Bruce told talkSPORT: "It is a difficult job. As everyone knows they have had five managers in five years and it just proves how difficult it is.
"There is a big expectation up there with a big expectant crowd and it can be very difficult.
"You are given no real time. Di Canio might have been a different style of management but he won 2-0 against Newcastle, he beat Everton 1-0 and everybody was saying he was the messiah. Then he didn't win for five, six, seven games - the Premier League can do that to you.
"A manager is only as good as his players. The better and bigger players you have got, the easier the job becomes. There is no magic wand to management.
"There might be somebody who changes the philosophy and changes the style but if you are going to do that you need time. Gus Poyet played open and expansive football at Brighton. If he is to do that at Sunderland, he must be given time."
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