Lukaku missed several chances to put the game beyond the Three Lions in St Petersburg before he went off on 60 minutes, as the Manchester United striker finished the tournament on four goals, all of which he scored in the first two group fixtures.
However, Martinez was quick to praise the 25-year-old, who he managed at Everton from 2013 to 2016, insisting goals were not the only aspect of Lukaku's performances in Russia that should be analysed.
"I think Romelu had a fantastic tournament. I am delighted with his contribution, his contribution goes further than just scoring goals," Martinez told a news conference.
"I appreciate Romelu's mentality, he's a winner, I don't think he has any worry about playing in big games. He's a perfect number nine for us.
"His power, his capability of scoring goals and moving defenders around and occupying defenders, I couldn't be happier with what he has done.
"He didn't start the tournament to be top scorer, he didn't come here for himself, he came here to help the team and that is a real sign of his maturity and he's got one of the brightest futures in Belgian football at such a young age.
"He has done incredibly well to be in the starting line-up [against England]. It was a really difficult game against France, he had a couple of knocks and was carrying a bit of a pain, but he wanted to be part of the team and to help."