Rooney, who has scored just once in eight internationals during the past 12 months, struggled to make his mark during England's opening 1-1 draw against the USA and must perform at his best if the Three Lions are to progress at the World Cup.
Gerrard said: "Wayne needs a goal, of course. I said all the way through qualifying that, if we got to the World Cup, we'd need Wayne to be our top goalscorer.
"We need him to score the goals to take us to the later stages of the tournament because he's our main player."
With holding-midfielder Gareth Barry set to return to the starting line up against Algeria, Gerrard will play in a more advanced role and is relishing linking up with Rooney in Cape Town.
"I think the plan is for me to get closer to Wayne and we've had a fantastic understanding in qualification. I like playing with good players - and I enjoy playing with Wayne. I'll certainly be looking to link up well with him. Hopefully I can provide a goal for him to get off the mark."
England are expected to take all three points against Algeria, who beat Slovenia in their opening game, but Gerrard has warned against taking anything for granted.
"The dangerous thing now is to underestimate Algeria and think it's an automatic three points, which it's not going to be," Gerrard said. "We've prepared really well for this game, the lads have been really sharp in training, and I feel we're ready to put in a sharp performance.
"The idea is to put on a good performance as soon as we can. We didn't manage that against the USA and we never clicked for the whole 90 minutes. Hopefully that will happen against Algeria and then everyone will be a lot more positive after the game."
Gerrard impressed against the USA in scoring England's goal, despite his more withdrawn role, but is looking to sustain that form.
He said: "It's always important when you go into a big tournament to put in a big performance first of all and to get a goal is an extra bonus.
"It helps you to settle and takes some of the pressure off so it was an encouraging start to the tournament but I need to continue that now to the end."