The 25-year-old former Davis Cup player needed only an hour to overcome his German opponent, conqueror of Jeremy Bates in the last 16. Apart from the pounds 4,615 first prize, Wilkinson gained 60 computer points to move up from 134 in the rankings to a best-ever 114.
"I feel that this could be the breakthrough I've been looking for," said the No 4 seed, who dropped only one set en route to his second Challenger success.
"I've said that in the past, I know," added Wilkinson, a quarter-finalist recently at the Hall of Fame Tournament in the America. "But this time I feel different. I'm starting to have more belief in myself."
Wilkinson broke the German in the fifth game and then held serve for the rest of the first set. He broke twice to lead 4-1 in the second before being broken himself, but after Saceanu had cut the arrears to 5-4, the grateful Briton served out for the match.
There was more British success in the men's doubles final, where Tim Henman partnered Mark Petchey to a 6-4, 6-3 victory over the Italian combination of Massimo Bertolini and Diego Nargiso.
Thomas Muster swept aside the unseeded Swede Jan Apell 6-2, 6-2 to win the Mercedes Cup in Stuttgart - but only after an amazing comeback in a rain-delayed semi-final against his great rival, Sergi Bruguera.
When the match was suspended on Saturday Muster had saved four match points but still trailed 3-5 in the second set, having lost the first 7-6. He levelled by winning the second set on the tie-break, then overran a dispirited Bruguera 6-2 in the decider.