Rangers triumphed at Stamford Bridge for the first time in three decades when Shaun Wright-Phillips fired an outstanding 78th-minute winner in a 1-0 victory against his former club.
It was a precious three points that could yet prove pivotal to the club's Premier League survival bid and, while they remain at the foot of the table, hope has returned to Loftus Road.
Just hours earlier Redknapp had been lamenting the decision of Liverpool playmaker Cole to reject QPR in favour of returning to boyhood club West Ham.
"I lost Joe who would have been my first signing. He probably looked here and thought, 'Harry, I love you, but you're not going to stay up'," Redknapp (right) said.
"I like Joe and he would have been good for me. He's West Ham and they love him there. I thought he was coming for sure but West Ham came in yesterday."
Only goal difference separates QPR from 19th-placed Reading and while they remain five points away from safety, Redknapp hopes the conclusion of their three-match losing streak will provide the springboard to climb the table.
"That was our first away win in the league since October 2011. Let's hope we can build on it.
"There's still a long way to go but that was encouraging," Redknapp said.
"I said to (assistant coach) Joe Jordan after the game, 'I cant remember having many better games than this one'."
The defeat all but extinguished fourth-placed Chelsea's fading title hopes and they now trail leaders Manchester United by 14 points.
Interim manager Rafael Benitez left Ramires, Juan Mata and Eden Hazard on the bench but his side still created more than enough chances to win a fifth successive match.
The Spaniard admitted Fernando Torres, Chelsea's only striker, needed a rest but refused to elaborate on the club's pursuit of Demba Ba after Newcastle revealed their £7million striker is having talks at Stamford Bridge.
"If we can do the business quickly hopefully he'll be available for the weekend, but we can't say too much," he said.