The Tigers head coach put his faith in a revamped team after the loss of Aaron Mauger, Harry Ellis and Matt Smith following late fitness tests and then Dan Hipkiss withdrew with illness.
And despite scoring first, Tigers trailed 26-8 before fighting back to earn a 32-32 draw – and a try bonus point - in front of a 20,000-strong crowd at Welford Road.
“The situation with injury, illness and unavailability was horrendous, but this club prides itself on spirit and passion,” said Cockerill after a thrilling Heineken Cup opener.
“The players were fantastic. Billy Twelvetrees had to come in at short notice for his debut, Lucas Amorosino came in for his first start, Craig Newby had to come on at half-time and play at centre. We were down to the bare bones against a world-class side.
“You cannot buy what we saw out there today. You cannot buy that spirit, that emotion and the feeling the players have for the club and for each other.”
Cockerill admitted his concern as the Ospreys cancelled out a second-minute score from Johne Murphy and raced into a 26-8 lead, but said his side just had to “go for it” in the second half.
“It was a titanic battle, we made a great start then had a horrendous 15 minutes before half-time,” Cockerill said as Jeremy Staunton grabbed the crucial fourth try after earlier scores from Murphy, Twelvetrees and Amorosino.
“We came in at half-time on the back foot but then went out and just had to play because you can’t sit back against a good side like the Ospreys.
“We took it to them because we had to. We came back to get the draw and I think we could have won.
“You earn the right to play for this club and in that shirt, and every single one of the guys did that today.”
