When Hillary Clinton pointed out that he supported the war, Trump repeatedly said the word "wrong" as she spoke. Trump then denied it over Holt's protestations, saying the media has peddled a lie about him.
Trump did publicly oppose the war, but not until after it started. Clinton supported the war as a member of the U.S. Senate.
Trump also strangely claimed that Clinton had been fighting ISIS "her entire adult life," despite the fact that the terror group did not come into existence until after the Syrian civil war started in 2011.
Markets seemed to react to Clinton making headway against her GOP rival as the debate progressed.
U.S. stock index futures erased losses to trade higher amid the debate, and the Mexican peso reversed losses to trade more than 1 percent stronger against the U.S. dollar.