Hughes was quickly appointed as the Argentine's replacement in the dugout and, speaking after the Welshman's maiden win in charge of the club, Bertrand was quick to sing his new manager's praises.
"The commitment and intensity has changed since the manager has come in," the England international told BBC Sport. "We have to apply that to our season.
"We competed and matched their aggressiveness and our quality came through.
"It is about learning a new system. We have two strikers up front and we don't want to starve them of the ball."
Southampton return to Premier League action after the international break on March 31 when they travel to West Ham United in a relegation six-pointer.