Around 7,000 fans attended the match - a sell-out crowd due to Covid-19 restrictions which limited the stadium’s capacity to 25 per cent.
Marcus Rashford captained the Three Lions and scored the game’s only goal from the penalty spot in the second half.
Southgate made nine changes from the team which beat Austria earlier in the week as he managed the squad’s workload ahead of this summer’s tournament.
Tottenham captain Harry Kane was rested for the match, yet supporters still got to see stars such as Rashford, Jack Grealish and Jadon Sancho in action from the start.
England now have a week to prepare ahead of their Euro 2020 opener against Croatia at Wembley on Sunday, June 13.
Here are some pictures from the Romania match.