Peter, dubbed the Nigerian nightmare, keeled over backwards and never looked like making the count as the fight came to a dramatic end.
Peter, who had won 34 of his previous 37 bouts, had never been counted out before.
"Samuel Peter is a very aggressive boxer. I have great respect for him and he fought to the last punch," said Klitschko, 34, in the ringside interview.
But with the brothers not fighting each other and Haye repeatedly refusing a much awaited unification clash with them, any other bout looks like an inexpensive substitute.
Peter, WBC champion for six months in 2008 before losing to Vitali, fought Vladimir five years ago and despite knocking the Ukrainian down three times on that occasion, ended up losing.
This time, he was the second choice for the fight after Russia's Alexander Povetkin failed to show up for a pre-fight news conference because of a sinus problem, prompting the IBF to order Klitschko's management to find a new opponent.
Klitschko controlled the fight from the second round, hurting the Nigerian with some left-right combinations.
He struck Peter with a vicious uppercut in the sixth round, by which time the Nigerian already had a swollen right eye.
Klitschko used his jab to wear down his opponent and by the ninth round, his win looked only a matter of time.
Klitschko finished the fight with one minute and 22 seconds of the 10th round remaining.
(Writing by Brian Homewood in Berne; Editing by Justin Palmer)