Look past the jab and watch for the heavy right cross.
Deflect to the outside with a simple hand parry as you circle step out and back letting your opponents attack move by you.
Use your free (R) hand to grab your opponents wrist or forearm, pulling back so as to put stress on his elbow with your chest. At the same time, thrust your other arm past his head and push back on his face as you kick out his leg and hips. This will buckle his balance and quite easily lead to a takedown as you sweep him back. It can also lead into an armbar, a reverse headlock, or to gain his back.