The victim had been followed by the attacker and pushed to the ground before being seriously assaulted.
The woman tried to fight off her attacker but he repeatedly punched her in the face, causing serious injuries.
Tahir was later arrested on September 28 after further detailed CCTV analysis was carried out.
Detectives said he was wearing the same clothing and carrying the same bag as the man captured on CCTV following the September 24 attack.
He was later charged with two counts of attempted rape after his DNA matched samples taken from both victims.
Tahir pleaded guilty to both offences at Snaresbrook Crown Court on December 17 and was today handed a total of 12 years in prison.
Detective Constable Adam Knott, from the Sexual Offences, Exploitation and Child Abuse Command, said: "Usman Tahir actively sought out, targeted and preyed on lone vulnerable females late at night for his own sexual gratification.
"I would like thank his two victims and acknowledge their courage throughout this investigation. Both were determined to attend court and see justice done.”