Assuming you're not organic spray it with Verdone Extra weedkiller available from most DIY outlets. It kills weeds but not grass.

The short answere is - you don't! Spraying with Verdone will slow it down and kill some of it, but not all and it will keep coming back. I keep digging buckets full out.

It does depend on the spraying regime . It says spraying with Verdone once a season is enough. It isn't but using verdone on a lawn perhaps 3 times per season until the core weeds are eliminated should be effective. After that once or possibly twice a year is enough