The answer is, without a shadow of a doubt it can defend, will defend and probably die defending.
But let's take a look if China decides to mean bussines and it dispatches not it's Research vessels in
Panatag Shoal but one of heir prized aircraft carriers.
As you can see in the picture and data above, there is no way Gregorio Del Pilar can win a fight against the giant Shi Lang.. Shi Lang is an aircraft carrier that can release fighter jets at will. Let's just hope Shi Lang forget's to bring her fighter planes.