The phrase "amazed watching" is correct and usable in written English.
It can be used to express a feeling of wonder or astonishment while observing something.
Example: "I was amazed watching the breathtaking performance unfold on stage."
Alternatives: "astonished by observing" or "impressed while viewing".
"I admit I was amazed watching the replay.
"He played a big, important role in the Spartak game but I was amazed watching him down at Kilmarnock - the best performance of the season from Brown," said MacLeod.
He's always amazed watching hotshots play around with a lot of other people's money, but he was stunned when he found out that the guys running Long-Term Capital Management L.P. had made bets on more than a trillion dollars of securities, in many cases without putting up any margin at all.
If poetry could tell it backwards, true, begin that moment shrapnel scythed you to the stinking mud... but you get up, amazed, watch bled bad blood run upwards from the slime into its wounds; see lines and lines of British boys rewind back to their trenches, kiss the photographs from home- mothers, sweethearts, sisters, younger brothers not entering the story now to die and die and die.
I'm also always amazed to watch how much progress a really motivated student can make over the course of a year.
Tom Claps, 37, a flight test engineer, said he was amazed to watch his fellow engineers, holding signs, chanting and throwing more wood in the blazing barrel to keep themselves warm.
Kevin Maguire from the Mirror added: "It is as boring as hell, I'm amazed anybody watches it".
I was amazed to watch people singing, clapping and dancing in the aisles with broad smiles during this tragic time.
I have had the great good fortune to know the actress Mae Whitman personally since she was a little girl; like any doting adult, I have been proud and amazed to watch her grow from an incredible child to a beautiful, astonishingly talented woman.
Thomason said it was "amazing" to watch thousands of people coming to see the art.
Mike Jackson, chief executive of AutoNation, said it was "amazing" to watch the speed at which Ford had slashed production and begun switching from trucks to cars: "The old Detroit would have taken ages to come to terms with this".
