Wales held World Cup-bound Mexico to a goalless draw in front of a huge 82,345 crowd at the Rose Bowl in Pasadena.
Manager Ryan Giggs gave opportunities to young players in his first two games in charge at the China Cup in March, and he did the same again in California.
Brentford defender Chris Mepham was outstanding in making his first start, and Leicester forward George Thomas, 21, and Manchester City midfielder Matt Smith, 18, both made second-half debuts as more youngsters were sent on.
“It’s great to see these young players come through and hopefully there’s many more caps to come,” Ledley said.
“There’s a good mixture here, with the youngsters coming through and a lot of experienced players. I think we’ll see that in the next campaign.”
Wales’ next games are in September when the inaugural Nations League campaign gets underway.
Giggs’ side host the Republic of Ireland in Cardiff before travelling to Denmark, and Ledley believes they will travel with confidence after frustrating Mexico.
“It wasn’t that long ago we played Mexico at this time of year and lost 2-0, so we’ve come a long way from there,” he said.
“They’re in the World Cup and we always knew it was going to be a difficult game.
“Some of us finished our season two or three weeks ago and we were always going to be up against it.
“But we worked our socks off and showed our character. It was a great performance.”
Ben Davies was particularly impressed with 20-year-old Mepham, who showed his maturity after skipper Ashley Williams succumbed to a suspected rib injury in the 17th minute.
Mepham was both vocal and organised as he and 23-year-old Bristol Rovers centre-back Tom Lockyer claimed a memorable shut-out against opponents ranked 15 in the world.
“Losing Ash was a big blow but the boys who came in did ever so well,” Tottenham full-back Davies said.
“It’s something to build on for both of them, but Chris deserved to start the way he’s been training. People will say there’s a lack of experience there but it doesn’t matter when he’s shown the quality he has.
“The manager has shown faith in those who have done well on the training pitch and I think that’s right.”
Germany’s captain and goalkeeper Manuel Neuer will return to international action in Saturday’s World Cup warm-up match against Austria after more than eight months on the sidelines because of a fractured foot.
“Manuel will play, there’s nothing against that,” said goalkeeping coach Andreas Koepke from Germany’s training base in Eppan, Italy.
“These are matches he needs, it’s a real test. Afterwards, it will be up to us to decide if it’s all OK.”
Germany coach Joachim Loew has already said that Neuer would only travel to Russia for the June 14-July 15 World Cup as the number one goalkeeper.
Loew has taken 27 players with him for their training camp, including four ‘keepers, with four to be cut before the list of the official 23-man squad is delivered to FIFA on Monday.
Neuer, 32, took to the field for the first time since his injury on Monday, playing 30 minutes in a friendly against the German under-20 side. He was to repeat that against the same opposition on Wednesday.
“Manuel needs these matches to once again be on 100 percent top form. They’ll help him to refind his confidence,” said Koepke.
The assistant coach added: “In training, you can’t see any difference (with Neuer), it’s as if he’s never had a break.”
Should Neuer come back, Barcelona ‘keeper Marc-Andre ter Stegen will find himself relegated to the bench after a year of filling in at number one.
“He knows the situation,” Koepke said of Ter Stegen, with whom he and Loew have had talks over potential selection issues.
“Manu is our captain, a world champion. We’re trying everything so it works out for him. Obviously Marc-Andre would love to play, but he can manage the situation.”
Egypt, Saudi Arabia, Morocco and Tunisia will represent the Arab nations at the World Cup this summer.
With less than three weeks to go until football’s greatest showpiece gets underway, the Arab nations will be stepping up their preparations with warm-up games before departing for Russia.
With Tunisia and Saudi in action in Monday’s friendlies, we take a look at how the respective nations fared.
PORTUGAL 2-2 TUNISIA
Tunisia pulled off a sensational comeback in their World Cup warm-up with a Cristiano Ronaldo-less Portugal in Braga.
It looked like the European champions were edging towards a facile victory having gone 2-0 up within 35 minutes, but a goal before half-time from Anice Badri kept the visitors within touching distance.
With 25 minutes remaining, Fakhreddine Ben Youssef capitalised on a loose ball to complete Tunisia’s fightback against Fernando Santos’ side.
The Eagles start their World Cup campaign against England on June 18, before going on to play Belgium and Panama.
ITALY 2-1 SAUDI ARABIA
Saudi Arabia suffered a narrow 2-1 defeat against Italy in St. Gallen, Switzerland in their opening warm-up match.
The Green Falcons struggled for large spells of the first half, with Nice striker Mario Balotelli scoring in his first international appearance in nearly four years on 21 minutes.
Torino star Andrea Belotti converted Italy’s second after the break before Al-Nassr hitman Yahya Al-Shehri pulled back a consolation goal for the Arab side.
Saudi will take on hosts Russia in their World Cup opener on June 14, before going on to play Uruguay and Egypt in Group A.