Navarino’s 1827 disaster turned Mehmed Ali toward independent military action.

Evidence

As was shown above, the crucial turning point came during the Greek war when he first agreed to send some of his newly trained troops to fight alongside the Sultan’s forces; after suffering from the major disaster of Navarino in 1827, he seems to have decided not to assist the Sultan any more and to engage in his own military exploits instead, even if these were at the expense of the Sultan himself. — Khaled Fahmy, All the Pasha_s Men_ Mehmed Ali, his…, 1667