The erosion of Liberal support continues in southwestern Ontario.

The region was once a Liberal stronghold, with heavyweight cabinet ministers holding down the fort.

But it will likely be without a cabinet minister for the first time in a decade as the NDP has swept the province’s three most southwestern ridings; Windsor West, Windsor-Tecumseh and the rural riding of Essex.

In a tight race, the NDP’s Lisa Gretzky stole Windsor West from Liberal Minister of Children and Youth Services Teresa Piruzza.

The NDP put a lot of effort into winning the Windsor West riding and maintaining the other two.

NDP Leader Andrea Horwath made three trips to Windsor during the campaign. She was there as recently as last week.

Liberal Leader Kathleen Wynne came to Windsor once, to participate in a collective campaign kickoff for a number of candidates about a month ago.

"We knew we were a target," Piruzza said in defeat. "I'm sorry, my apologies."

With 245 of 246 polls reporting, Gretzky had 14,949 votes to Piruzza's 13,957.

The Liberals won a majority government Thursday with Piruzza being the only Liberal cabinet minister to lose her seat.

She took to Twitter immediately after the loss.

The ridings of Windsor-Tecumseh and Essex were never in doubt for the NDP Thursday. Percy Hatfield and Taras Natyshak ran away with the ridings, respectively.

Hatfield was one of the first MPPs to be projected a winner. Natyshak was projected a winner minutes later.

"We'll be the conscience of Ontario," Hatfield said of NDP MPPs.

He said Ontario wanted Liberal Leader Kathleen Wynne in the end.

"Now let's see what her budget is," Hatfield said.

Natyshak called Gretzky "a wonderful addition to our team."

He said he doesn't regret that it was his party that ultimately sent Ontario to the polls.

"We had to give the people the opportunity their say. It was time to go to the people," he said.

Until tonight, Liberals had at least one MPP in one of those three ridings since at least 1995.

Windsor West Graph

The NDP has been gaining on the Liberals in Windsor West since the riding was created in 1999. (CBC News)

Piruzza’s loss marks the first time in 11 years that no member provincial government will hold a seat in Windsor or Essex County.

"It’s probably not the best news because we’re missing a member sitting in the government and someone at the cabinet table. It’s going to be much more difficult to get our voice heard," University of Windsor political science professor Cheryl Collier said.

Windsor hasn't just had MPPs in Queen's Park, it's had cabinet ministers.

Former Windsor-Tecumseh Liberal MPP Dwight Duncan was named Minister of Energy in 2003, before eventually becoming the Minister of Finance under former premier Dalton McGuinty.

In 2004, Windsor West MPP Liberal Sandra Pupatello, who held the seat for 12 years, was named to cabinet. Kathleen Wynne last year named Pupatello’s protégé, Piruzza, the Minister of Child and Youth Services.

Liberals have been losing seats from London down through the last two elections.

'Dismal campaign'

In the Sarnia region, the Progressive Conservatives held on to a pair of seats. Bob Bailey and Jeff Yurek won Sarnia-Lambton and Elgin-Middlesex-London, respectively.

Sarnia Mayor Mike Bradley said the PCs ran "a dismal campaign."

Now, he thinks Wynne has some work to do in the southwest and make good on her promise to govern the whole province and not just the GTA. It's a promise she made the night she won the Liberal leadership.

"I would hope she'd respect that," Bradley said. "It's a great victory for her tonight, for her personally. At the same time, if she wants to govern all this province over the four years, she's got to reach out and listen to the people of this province and not just the ridings that are Liberal."

Wynne said she would do just that.

"We live in one Ontario and our job is to build this province up for every single person in the province," Wynne said during her victory speech.

Other projected winners in southwestern Ontario include:

Chatham-Kent-Essex

Rick Nichols of the PCs retained his seat in nearby Chatham-Kent-Essex, a riding hit hard by job losses recently with the announcement of Heinz leaving Leamington at the end of June.

Nichols said unions pushed the Liberals into a majority.

"Where do you go when you get all these unions pooling all of their union dues together and deciding who do they want to have as their boss?" he said. "And the primary criteria for that is simply this particular [party] will pay me more money than the others."

London North Centre

Liberal Health Minister Deb Matthews won London North Centre in a tight race.

"This is a historic night. Ontario has elected decisively Ontario's first female premier. We made history folks," Matthews said. "Kathleen Wynne is going to recall the Legislature right away, and we are going to re-introduce that budget, that very progressive Liberal budget, and this time, we're going to pass it."

The riding wasn’t without controversy during the campaign.

The Progressive Conservatives were forced to apologize Tuesday after the party said a campaign worker sent letters to homes in London North Centre that invited residents to vote on Thursday in the wrong location.

London-Fanshawe

The NDP’s Teresa Armstrong hung on to London-Fanshawe. It was her second straight win. She also knocked off a Liberal in 2011.

London West

The NDP’s Teresa Peggy Sattler held on to her seat just months after winning it in a byelection.

Elgin-Middlesex-London

PC Jeff Yurek held onto his seat for the second consecutive election. He won the riding from the Liberals back in 2011.

Sarnia-Lambton

The PCs retained their seat in Sarnia-Lambton, where Bob Bailey was victorious.

Lambton-Kent-Middlesex

The PCs’ Monte McNaughton won the seat he’s held since 2007 in Lambton-Kent-Middlesex.

Haldimand-Norfolk

Haldimand-Norfolk hasn’t been a contest since 1995 when Toby Barrett first won the seat. He won again Thursday night.