World number three Wawrinka needed just 31 minutes to collect the opening set but had to battle his feisty opponent a day after Ferrer had knocked out eight-time champion compatriot Rafael Nadal.
"It was the perfect start for me. I played very well in spite of the wind," said the winner.
"He was more aggressive in the second set, but that's when I played tougher."
Wawrinka could face an all-Swiss final for the first time at the Monte Carlo Country Club if Roger Federer beats holder Novak Djokovic, with the Serb complained of a wrist problem but keeping all details under wraps.
Also Read
The Swiss lost the Rome Masters final to Djokovic in 2008 and went down to Nadal in a Madrid Masters title bid last May.
Wawrinka improved to 19-3 on the season and has relegated his post-Australian slump where he lost early in both Indian Wells and Miami to ancient history.
The Swiss had not faced a break point until this meeting with Ferrer, improving his record in the series with the Spaniard to six wins against seven losses.
"Stan was very good, he was playing unbelievable," said Ferrer, who trailed 5-0 in the first set.
"I didn't return very well, but in the second Stan had a few mistakes and I was able to play with more power with my forehand.
"But Stan was better, and he moved the ball better than me."
Wawrinka proved unstoppable in the opening set, firing a forehand winner to the corner to earn the early lead. In the second the famed Ferrer resistance stiffened, with the sixth seed giving the Swiss a battle on the clay.
As the set went into a tiebreaker, Wawrinka lifted his level, taking a 4-0 lead and finishing the victory on the second of four match points as Ferrer put a forehand into the net.