After beating China 2-0 in round of 16, Italy reached their first ever quarterfinal since the inaugural Women's World Cup in 1991.
"Our defense is world class this evening, and I have to take off my hat to them," said Bertolini, who thought the victory offered a great gift to her 53rd birthday on Monday.
Italy just conceded two goals in four matches at the 2019 edition of quadrennial competition.
"Defending is not only the case of back four. When it comes to defending, we defend as a unit. The team all think about defending together. When we defend, it's about our mindset and mentality.
"As long as we lost the possession, we were reday to defend from forwards to the rest of the team," she noted.
For Bertolini, "The squad is made up of girls who have a lot of quality and talent. They are performing very well here in France because of that. They also have a sense of mission, which is to let the Italian public discover the women's game and appreciate it."
"That allows you to find extra energy and motivation," she said. "The team represents the whole movement of Italian women's football. Women are able to convey this football change in society day in and day out, and can lead to cultural changes ongoing in Italy. Cultural changes are always slow, but this team is able to break down prejudice and barriers, which is the mission of girls in France."
Despite having four fewer attempts than their Chinese counterparts, Italy managed a win through their clinical offense, making the most of space behind Chinese defenders.
"China approached the game in a way that we didn't expect," Bertolini admitted.
"We thought that China would shut and stop their play, but they pressed high on the pitch today. We found space behind their defensive line, which allowed us to exploit in this particular situation by playing balls in behind.
"Two Chinese center backs did better when they sat deeper, but didn't play their best when there was space behind them," she added.
"We had a great start in the opening 20-25 minutes. We wanted to press and attack them, and it was no surprise that we were able to score and had another goal ruled for offside.
"Then we started to drop back, because China came out and responded. We got a little bit scared.
"We really struggled. We had to keep a cool head because we have many technically gifted players. When it came to defending, we played well, and were very clinical in front of goal, which is very important in football," Bertolini said.
Bertolini took charge of the team in 2017.