San Juan - England skipper and hooker Dylan Hartley has hailed the young "terriers" in a severely depleted squad ahead of the first Test against Argentina in San Juan on Saturday.
Two uncapped teenagers - run-on flank Tom Curry and replacement lock Nick Isiekwe - have been included in the matchday 23 by Australia-born coach Eddie Jones.
British and Irish Lions call-ups for the tour of New Zealand have robbed the Red Roses of 16 players and a total of 30 were unavailable for the two-Test series.
But Hartley, overlooked by the Lions while understudy Jamie George was chosen, has scoffed at the "C stringers" tag attached to the team by some pundits.
"The young guys have brought a lot of energy to training and I have been thoroughly impressed by what I have seen since our tour preparations began," he said.
"These youngsters are running the show and, as you would expect, the intensity has been ultra-competitive.
"They are hungry, keen to perform and know what is expected of them. They want to stake claims for regular positions in the squad," said the 31-year-old New Zealand-born forward.
Hartley dismissed the belief that Argentina will be a pushovers after woeful recent form by many of their national stars for the Jaguares in Super Rugby.
The Buenos Aires-based franchise - the national team in all but name - began the season with four wins in five matches, but have lost six of the last seven.
Recent defeats by Australian visitors Force and Brumbies would have been particularly worrying for Pumas coach Daniel Hourcade as the traditional Argentine fire was missing.
Apart from error-riddled performances and erratic place-kicking, injuries have hampered the Jaguares with star halfbacks Nicolas Sanchez (fly) and Martin Landajo (scrum) among the absentees.
Injuries to Argentine rugby icon Juan Martin Hernandez, who can operate at centre or flyhalf, also had a disruptive effect on the side.
However, Argentine rugby analyst Frankie Deges says injuries cannot mask all the weaknesses that could spill over from the Jaguares to the Pumas.
"The lack of cohesion and fighting spirit in recent matches means urgent intervention is needed by the national coach (Daniel Hourcade)," he wrote.
"The season is in free fall and the coach has only the Jaguares to choose from.
"(Let us hope) it is not just a case of changing the orange or black colours of the Jaguares for the blue and white of the Pumas."
Pumas skipper Agustin Creevy, like Hartley a hooker, does not believe poor Super Rugby form will necessarily translate into sub-standard Test performances.
"There is a positive attitude within the camp and we came close to winning in England last November," he said, referring to a 27-14 loss at Twickenham.
"We are aware of the many shortcomings in recent Super Rugby matches and have worked extremely hard in training to fix them.
"England are going to be very difficult opponents despite the absence of so many first choices.
"We must get used to their style of play as we face them again this November in London and at the 2019 World Cup in Japan."
Jones does not accept that a string of Super Rugby setbacks makes Argentina vulnerable at the 25,000-seat Estadio Bicentenario near the border with Chile.
"We know Argentina are a very good side having played them earlier this season and they will be desperate to win against us," he said.
15 Mike Brown, 14 Marland Yarde, 13 Henry Slade, 12 Alex Lozowski, 11 Jonny May, 10 George Ford, 9 Danny Care, 8 Nathan Hughes, 7 Tom Curry, 6 Mark Wilson, 5 Charlie Ewels, 4 Joe Launchbury, 3 Harry Williams, 2 Dylan Hartley (captain), 1 Ellis Genge
Substitutes: 16 Jack Singleton, 17 Matt Mullan, 18 Will Collier, 19 Nick Isiekwe, 20 Don Armand, 21 Jack Maunder, 22 Piers Francis, 23 Denny Solomona
15 Joaquín Tuculet, 14 Matías Moroni, 13 Matías Orlando, 12 Jerónimo de la Fuente, 11 Emiliano Boffelli, 10 Nicolás Sánchez, 9 Martín Landajo, 8 Juan Manuel Leguizamón, 7 Javier Ortega Desio, 6 Pablo Matera, 5 Tomás Lavanini, 4 Matías Alemanno, 3 Enrique Pieretto, 2 Agustín Creevy (captain), 1 Lucas Noguera Paz
Substitutes: 16 Julián Montoya, 17 Santiago García Botta, 18 Nahuel Tetaz Chaparro, 19 Guido Petti, 20 Leonardo Senatore, 21 Gonzalo Bertanou, 22 Juan Martín Hernández, 23 Ramiro Moyano