The footpath underneath the bridge, which leads to Wootton Way, was cordoned off with police tape until early this morning.
Some residents said they saw police cars and an ambulance in the road close to the bridge at about 11.30pm last night.
One householder, who has lived in the residential street for six years, described the attack as 'shocking'.
She said: "I saw blue flashing lights outside my house last night but I didn't realise someone had been stabbed.
"This is a quiet area and you don't expect things like this to happen. It's absolutely shocking."
Two men were arrested following the assault which left a man in his twenties in hospital in a serious condition.
He was attacked as he walked down Norden Road with a group of friends at around 11.15-11.30pm.
A group of men were driving along the street in a silver or white car before jumping out and approaching the friends.
A fight followed in which the victim was stabbed in the stomach before the attackers fled the scene in the same car.
The victim was taken to Wexham Park Hospital where he underwent emergency surgery and remains in a serious condition.
The car is described as being similar to a small Vauxhall.
The two men remain in police custody.
Anyone who witnessed the incident should contact Detective Inspector Nicola Denard on the non-emergency number 101 or Crimestoppers anonymously on 0800 555111.
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