Already qualified from Group F, the Red Devils fell behind when Tomasz Kuszczak allowed Abel's driven cross-shot from the right touchline to beat him at his near post in the 21st minute.
But Tevez, on as a half-time substitute, was credited with the scrambled equaliser before Cristiano Ronaldo scored his last-ditch winner from 25 yards out to ensure United claimed top spot in the group.
"The important thing in the second half was our impetus and the change of pace, and Tevez helped that with his positional play," Ferguson told ITV4. "His running caused them problems and I'm delighted he got the equaliser because he deserved that."
On Ronaldo's stunning winner, Ferguson said: "It was a magnificent strike but he's capable of that - he practices them all the time."