Command and Conquer 3

Heey guys I am still kind of new to the game and I tried going online for a couple of times now. One time I was doing Tournament Arena against a not very pro guy, but I managed to live and harass him a bit like I read in a few guides. But suddenly I see an engineer go into my MCV and boom he build a gunner (he was GDI btw) next to his (my) MCV and started building. I tried to recapture it, but my engineer wasn't able to get to the MCV in time before getting shot by the gunner.
Now for my question: What can I do to prevent an engineer rush?

With your warfactory make a buggy and 3 bikes. OR a couple of scorps and have good map awareness. Bring up some shredds if you need it.

Engi rush is fairly easy to counter, its when they use it when pushing is when its a bitch.

just scout then u can see it coming