72 hr visa waiver for Us citizens

I am a US citizen wanting to take advantage of the 72 hr visa waiver. I am travelling to india but want to break my trip in Beijing. I will reach there at 6pm on the 8th Mar and fly out on Mar 11 at 8 pm. I will be 2 hrs over the 72 hr limit. will this be a problem? There are no flights to India on the 10th. Please advise