Hi Hans,

It does look like crabgrass from the picture but it is hard to tell how it differs from your "regular" lawn without seeing a larger area that includes this clump.  In terms of control, it would be important to identify the culprit to be sure but if it is crabgrass, you can treat in the spring with a pre-emergent herbicide to control.  Any lawn service could do that for you or you can get a product at a big box store like Home Depot or Ace.  Timing is important with pre-emergent treatments so make sure you get that on early in the season - the instructions on the product should be specific about timing.  You can definitely bring a sample in to our county office for definitive identification.  Good luck!  Chris