Senegal midfielder Diame moved to the KC Stadium on transfer deadline day for a reported fee of £3.5million and is proving to be a big hit at the Yorkshire club.
The 27-year-old scored his third goal in just four appearances in Saturday's victory over Neil Warnock's men, meeting Andrew Robertson's expert cross with a thumping header.
Bruce is thrilled with the impact the former Wigan Athletic man has had on the team and is hopeful he can continue to produce the goods.
"I don't think it's the fact they [West Ham] didn't want him," he said. "I think everyone has to make a decision when he's got 10 months on a contract whether to cash in [or not].
"To be fair to [West Ham manager] Sam Allardyce he wanted a defensive midfielder player and I think allowing Diame to go allowed him to get Alex Song.
"We're delighted I'll tell you, he's been brilliant for us. He's played in the Premier League for the last six years and done it fantastically well in my opinion.
"I first came across him when he was at Wigan and he blasted one in, I think it got me the sack at Sunderland, but he's a good player, a really good player.
"He's got a right foot [goal], a left foot [goal] and now he's scored with a header.
"He is for me as a midfielder player, not quite complete, but he's big, he's strong, he's athletic, handles the ball well, good in the air, got two good feet and he's had a really good start. I hope it continues."
