In the bout at fabled Madison Square Garden, Klitschko on Saturday did little to impress US fans who have failed to jump on his bandwagon despite his seemingly impenetrable reign.
Klitschko improved to 65-3 with 54 knockouts, earning his 22nd straight victory and making his 18th straight heavyweight world title defense.
He is approaching the record of 25 title defenses made by American legend Joe Louis in the sport’s glamour division.
Klitschko, who put his International Boxing Federation, World Boxing Association and World Boxing Organization belts on the line, used his left jab to take charge early.
He used the advantage of his 1.98m hight – to Jennings’ 1.91m – to good advantage although the challenger, who was working as a janitor in 2004 when Klitschko last lost a fight, gave the champion some trouble with his quick movement and darting advances in the middle rounds.
Klitschko responded in the final round with some heavy blows, and even with the champion docked a point by referee Michael Griffin for repeated holding, the scorecards were not close.
Cheers were ringing and Ukrainian flags waving by the time the scores were announced. Two judges saw it 116-111 for Klitschko, while the third made it 118-109 for the champion.
Jennings, who fell to 19-1 with 10 knockouts, said he thought it was closer.
“I think that the scorecards were way off,” Jennings said, adding that he believed the fight “probably could have gone either way.”
Klitschko acknowledged that Jennings was more competitive than any opponent he had faced in recent years.