Help Identifying this weed
I am a home owner and had a huge area of my lawn taken over by this weed. I had the weeds killed, ground tilled cleaned of debris and Centipede sod replanted. It is very hot here right no so it have been watered daily and this darn weed is coming up through the sod as well as still growing in unsodded areas. Please help me identify it and kill sit without hurting my new sod.
two pics attached.