He had performed other valiant exploits; his ships were well equipped and manned, and the crews trained in modern warfare.
In addition, the city of Algiers was so strongly fortified that Lord Nelson declared that twenty-five ships of the line would not be more than enough to capture it.

As Decatur drew near the Portugal coast he made guarded inquiries as to the whereabouts of the Algerian squadron.
He used the utmost care to prevent his presence from becoming known to the enemy, and finally heard that which led him to believe the Moorish admiral had passed through the Straits of Gibraltar and entered the Mediterranean.

At Gibraltar Decatur saw several boats hurrying off to Algiers to warn his enemy of his danger.

He made sail up the Mediterranean, hoping to beat the despatch boats.

The admiral's flagship was descried, and, still striving to avert suspicion, the American ships worked gradually toward him.