Missing Atletico Madrid's defensive pair Jose Gimenez and Diego Godin, Tabarez handed debuts to 18-year-old centre back Bruno Mendez and 22-year-old full back Mathias Suarez, as well as a first start to goalkeeper Martin Campana.
All three did not let him down at the Emirates Stadium as Uruguay were unlucky to lose to Neymar's 76th minute spot kick.
Tabarez singled out Mendez, who more than held his own against a pacy Brazilian attack of Neymar, Roberto Firmino and Douglas Costa.
The veteran coach compared Mendez's debut to that of Gimenez, who played his first international match, also aged 18, in a crucial World Cup qualifier against Colombia in 2013.
"He showed things today that all talents show, they seem like they are wise beyond their years," Tabarez said.
"It seems like they have more experience than they actually have.
"That happens in small countries where there aren't that many footballers. Jose Maria Jimenez also debuted in very similar conditions to Bruno Mendez and now he has consolidated his international position."
Uruguay, with a population of 3.5 million, has no problem competing with bigger neighbours Argentina and Brazil, and has lifted the World Cup twice, while winning the Copa America 15 times, more than any of their rivals.
"So we don't have an abundance. When one player appears in Uruguay, 10 appear in Argentina and 40 in Brazil," added Tabarez.
"But it encourages the hope that we can be competitive against teams that maybe have more potential than we have."
Brazil won the decisive penalty after Danilo was brought down in the box but Uruguay claimed there was a handball in the build-up.
"We were very much the equal of Brazil, we had chances, they had, too," Tabarez said.
"It's a shame the match was decided by a controversial incident, the game didn't deserve that."
(Reporting by Andrew Downie; Editing by Ian Ransom)
