Would Einstein been able to formulate general relativity without metric tensor

Would Einstein been able to "solve" his general relativity field equations without the earlier mathematical work or Riemann's metric tensor?

Or would he have "discovered" the metric tensor himself, like Newton "discovered" calculus in order to solve his equations?

I'll ask the same questions in math and physics sections to see what different responses I get, if any.

This is an opinion question, but having read Einstein's life, he was so desperate 3 years into his quest for general relativity that he asked his mathematician friend Grossman who came upon Riemann's metric tensor by accident!

So in my opinion, no I don't think Einstein had the mathematical skills to solve the general relativity field equation without Riemann's earlier work.