The 26-12 victory came 11 years today over their only other victory in the Millennium Stadium, and it followed a promising - if winless - debut campaign in the Rugby Championship.
A magnificent second-half performance in Cardiff earned them victory over the Six Nations champions and Ayerza says it proves they are moving in the right direction.
"We didn't have control of the game in the first-half," Leicester prop Ayerza said. "The scrum and the line-out weren't going our way, but we came back into the game.
"Playing games against the best sides in the world and playing at a high tempo and intensity can only help us to develop.
"You saw that against Wales. We played 80 minutes at a very good intensity, and this win is massive for us.
"It shows we are going in the right direction and that we are improving as a nation. To beat Wales at the Millennium Stadium is a huge achievement, one that we are very proud of.
"This year has been our first season in the Rugby Championship, and there is no doubt we will continue to improve.
"Now, we have two more massive games coming up against France and Ireland. They will be tough, but this win will have given us extra confidence."
Skipper Juan Martin Fernandez Lobbe led from the front with a magnificent display - a fitting way to mark his 50th cap.
And Ayerza added: "He is such a talisman for us, such a positive influence in so many different ways.
"He is one of the best captains I have ever played under, and he always shows the way with his performances. He always gives 100%."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The Barbarians are one of the top invitational rugby sides with a long history and classic rugby jersey.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Lions get ready for their matches with this green training jersey. It's what the players wear. Get in the Gear!
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The Lions are ready to get their Australia tour underway. They arrive in Perth on Monday.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.