The Dutch side stunned Champions League holders Real Madrid in the last 16 by completing a 5-3 aggregate win with a 4-1 victory at the Bernabeu on Tuesday.

Former Ajax player De Boer - who spent four years at Ibrox from 2000 - is a youth coach with the Amsterdam club.

"You have to have an identity with your players," he told BBC Scotland.

"If you have 11 foreign players, people don't care if the results are there. If you have your homegrown player, people would rather see that than a player who you bought for a lot millions.

"Your resources are limited but if you focus on the youth from six and seven years old, the whole organisation can be built up. That's what I see in Holland from the amateur teams to the pro teams.

"You have to have a philosophy of where you want to be in a certain stage. I think that's very important, so if you put a timeframe, I think in 10 years you could have some results."

Scottish Premiership title holders Celtic failed to reach the Champions League group stages this season, but reached the last 32 of the Europa League while Rangers featured in the group stage of that competition.

De Boer won the Champions League with Ajax in 1995, beating AC Milan with a team dominated by Dutchmen when the use of foreign players was restricted to three in European competitions.

The Dutch side then beat Real home and away in the following season's competition, but Ajax's win in Spain this week was even more impressive, according to the former Netherlands forward.

"Now, if you are a team like Madrid and your right-back doesn't do the job, you buy the best right-back in the world and can fill your team in with 11 foreign players," De Boer said.

"Ajax can also buy foreign players, but we stick with our philosophy and still managed to beat Real Madrid with so many youth players."