Roland Garros saw its queen dethroned when Justine Henin suffered a shock defeat on Monday, but 17th seed Schiavone played like her heir apparent on Philippe Chatrier Court, her all-court game simply too much for teenager Wozniacki.
Schiavone won 6-2 6-3 in one hour 20 minutes to become the first Italian woman to reach the last four of a major in the Open era.
The 29-year-old got past the first week of each of the previous three grand slams before arriving in Paris but she had not been in the last eight at Roland Garros for nine years.
Comparing the feeling to a "heart attack", she said: "I think in that moment you remember many things from when you were young.
"It's special because it is your space, it is your time, it is your opportunity. I felt alone, but with all the love around.
"It's like if I ask you, 'How did you feel when you married?' You say, 'It's not easy to explain'."
Few players can have reached a grand slam semi-final having waited so long to do so. This is Schiavone's 39th attempt in total but she insisted she never gave up on her "dream".
Third seed Wozniacki admitted she was beaten by the better player. "She played with a lot of spin, she didn't make a lot of mistakes, she played aggressively," the 19-year-old said.
"She was playing better than me today. I was always one step behind and couldn't really dominate the way I wanted to."
In stark contrast to Schiavone, opponent Elena Dementieva will be contesting her ninth grand slam semi-final.
Her error-strewn match with Nadia Petrova could not have been more different either, as both players struggled with leg injuries picked up earlier in the tournament.
Dementieva capitalised on her fellow Russian's discomfort to win 2-6 6-2 6-0 in two hours and six minutes.
The 28-year-old two-time grand slam finalist, runner-up at Roland Garros in 2004, said:
"This is one of the biggest goals left in my career. This is great motivation for me."
Both players took medical timeouts at 3-2 to Petrova in the first set.
The 27-year-old, who upset Venus Williams in the last round, admitted she had considered quitting in the decider with a groin injury she picked up in her marathon third-round victory over Aravane Rezai.