Dike's 60th-minute goal - his first at The Hawthorns a year and a day since signing for £7million - was the only one Albion managed in the match despite a glut of first-half chances, but was enough to move them within a point of the play-off zone.
Okay Yokuslu, Jayson Molumby, Conor Townsend - who also hit the post - and Dike all missed opportunities in the 1-0 triumph while Royals goalkeeper Joe Lumley made three vital saves before Dike's diving header from Molumby's cross proved the difference.
"He had a long-term injury but he's a very important player for us," Corberan said of Dike.
"The fitter he is, the better it is for the team. The more he trains, the better condition he's in to perform.
"So there isn't any doubt that he's one very important player for us that we need to keep controlling, because he's one player that we need in the box."
Corberan added: "I think sometimes he plays against himself because he tries to do a lot of things.
"In the first half he made a lot of runs but not all in the right areas. But in the second half he was in the areas he needed to be a lot more."
Corberan, whose side extended their record of not conceding a goal in open play to 877 minutes, acknowledged Albion had to be patient after being kept at bay before the break.
"When you don't score, you can try to do something else and sometimes, something else is something less," he said.