Rashford scored in England’s matches against Spain and Switzerland, moving onto five international goals.
Southgate praised Rashford’s development, comparing him to Juventus star Ronaldo – who was at the beginning of his United career at the same age – and Tottenham forward Harry Kane.
“He is [a special talent],” he told UK newspapers.
“Even if some of those other top players who have broken into the team, some of the step-overs and things Ronaldo was doing at that age, but he wasn’t converting them into the number of goals, so we have got to give him time to develop.
“He [Rashford] has still played a lot of football, although maybe not the continuous starts and I’m really pleased for him that he leaves England full of confidence. He’s got huge competition for places at his club, so you can understand [his frustration].”
The first time Kane struck more than nine in a campaign was in 2014-15 – as he approached 22 years of age – but he netted an impressive 31.
“It’s not my business to interfere with club managers, they have a difficult job to do and they have big squads at the top six, huge competition for places, so Jose thinks the world of Marcus,” he said.