City keeper Andy Marriott dropped the ball at his feet to clear without noticing that Robbie was still behind him and the Irish star nipped in and gleefully rolled the ball into the empty net.
It was the perfect start to the afternoon and Gus Poyet applied the perfect finish three minutes from time with a magnificent volley to grab maximum points after Paul Devlin had levelled from the penalty spot.
A delighted Glenn beamed: "Robbie's goal was possibly the cheekiest you'll ever see, the sort of thing Jimmy Greaves would have done.
"It's been a very difficult week for Robbie so I'm sure he'll remember that goal for a long time and keep the memory of it for his dad.
"Football can be a release from something like that and what he's done for the Republic of Ireland and us this week shows what a strong character he is.
"It was a unique goal. You've got to feel for their keeper but it was a bit of good thinking by Robbie.
"He's tried it a few times. He persisted and it came off - I'm delighted for him."
Glenn Hoddle likened Robbie Keane's opportunist goal to something the great Jimmy Greaves might have done after Saturday's vital 2-1 win against Birmingham City.