infantry against tanks certainly gives you more respect for the humble german infantryman or his allied counterparts doesn't it? I find generally that if the enemy doesn't use good infantry/ tank combined arms strategy they can be ambushed, but it gets harder if they do know what they are doing. The tanks can crush at range, and the infantry can find ambushes... Still the panzerfaust range and commonness does help if sie sind deutsch.

AT guns can work much better, in some of my harder CC3 campaigns I used them a lot. The key thing is hoping that they either hit with the first shot or if they missed then so did the tank!

And of course, flamethrowers kill tanks megadead at close range... problem is as Alexander said, close range for a flammenwerfer is basically "nozzle in the drivers viewslit" style distance.

You just gotta do it Soviet style, and throw all those different things at them and hope one kills em.