Actually, Israel was losing for the first several days
of the 1973 Yom Kippur War. They were caught flat footed on the most holy day of the Jewish year. Many of their front line troops were home celebrating the holiday with their families. When they tried to rejoin their units, ultra orthodox extremists threw rocks at their truck convoys.
It wasn't until several days after the start of the war that Israel turned the tide of battle. Before that point, there are reports that they brough out their nuclear weapons to a special attack squadron and were preparing to use them. The US saw this on our satellite photos and went to our highest state of alert. It was a very close thing.
