Senegal star Cisse told Sky Sports News in an interview translated by strike partner Demba Ba that he went for goal because he was so tired.
Cisse: "I just saw the ball coming back from Shola (Ameobi) and I just wanted to shoot as I had no power, so I just shot."
The 26-year-old's 25-yard banana volley with the outside of his right foot brought back memories of Roberto Carlos' free-kick for Brazil against France 15 years ago.
Alan Pardew: "An astonishing goal. Cisse took a chance. You could see he meant it and he's hit it absolutely true.
"A team challenging for the title, a team challenging for the Champions League.
"If someone had said that to us at the start of the season, we probably wouldn't have believed them.
"We were seeing the game out at 1-0. I thought we'd get home with the goal that we had, but Cisse took a chance.
"You could see he meant it and he hit it absolutely true.
"It means so much to win here after 18 attempts.
"The players should be immensely proud. It was an unbelievable performance.
"I'm confident Cheick Tiote will be fit for Sunday's clash with Manchester City.
"A nine-inch gash, 400 stitches, but it's just a scratch to him.
"He'll have a little patch on him on Sunday and he'll play."
If two of Newcastle, Tottenham and Arsenal win this weekend, Chelsea's top-four bid will be over, leaving them having to win this month's Champions League final to qualify for next year's competition.