Both were giving evidence on the second day of the inquests into the deaths of Christopher Loftus and Kevin Speight.
They were in Istanbul, Turkey for the Uefa Cup semi-final against Galatasaray in April 2000.
Mark Valentine told West Yorkshire coroner David Hinchliff that he was drawn to a man lying on the ground with a blood-stained shirt and another man standing near the body holding a knife blade.
He ran to the injured man, who he recognised as Mr Loftus, and started administering mouth-to-mouth resuscitation but continued to be attacked by Turkish fans.
Peter Hopton was another fan to offer assistance and he told the inquest how he too gave Mr Loftus mouth-to-mouth.
Both witnesses also claimed to have been struck with batons by Turkish police while trying to help.
A 22-year-old man was jailed in May 2002 for killing Mr Speight, who was 40 and from Farsley in Leeds, and 35-year-old Mr Loftus who lived in Burmantofts, Leeds.
Last year, an appeal court overturned his sentence and ordered a retrial.