Lukaku popped up to score the winner in the 2-1 triumph at Goodison Park as Everton atoned for Boxing Day's defeat to Sunderland, their first home league loss of 2013.
And despite a barren spell for Lukaku, Martinez insists there was never any doubting the ability of the Belgian, who he insists has made great strides this season.
The Spaniard said: "I think from the outside looking in you are going to judge a striker on their goalscoring ability and the numbers.
"But Romelu, when he arrived here, he was a young player and he couldn't play 60 to 65 minutes.
"For me if he scores goals, yes it's magnificent, but for me I judge him by all the different aspects of his game.
"We've been working on other aspects of Romelu's game and were never in a position to worry about his goals. He attracts two or three players."
Roberto Martinez also backed Spanish stand-in goalkeeper Joel Robles after he allowed Gaston Ramirez's 35-yard effort to dip under his hands.
The 23-year old replaced the suspended Tim Howard for his first Premier League start for the Merseyside club.
But Martinez insisted that the former Atletico Madrid man was not to blame for the visitors' goal, maintaining that he was happy with the performance of his keeper and the team as a whole.
He said: "I thought Joel had a good game - he was in control of his box and playing with a new defence.
"Joel is blaming himself (for the equaliser) but I don't think that's the case. These balls swerve everywhere and he (Ramirez) struck it well.
"I thought it was an extremely good game of football and I couldn't be happier with the overall performance."
