What television show is considered the "unofficial" pilot for Rod Serling's original "Twilight Zone" series?

In 1958, writer Rod Serling was known for his strong dramatic television writing that had won him three Emmy Awards for Patterns, Requiem for a Heavyweight, and The Comedian. Branching out, he wrote a time travel story entitled The Time Element, about a New York bartender (veteran comic actor William Bendix) who has a recurring nightmare that he's in Pearl Harbor, Hawaii on the night before Japan's sneak attack, but can't convince anyone of what's going to happen. The thrilling story landed at Westinghouse Desilu Playhouse, and when it debuted in 1958, CBS received thousands of positive letters, indicating the public's desire for more fanciful stories like The Time Element. It was this reaction that helped Serling successfully pitch The Twilight Zone to the CBS executives and their sponsors. A formal pilot episode was later shot with Earl Holliman, entitled Where is Everybody? and that has become the official pilot for the show - and the first episode ever aired. But The Time element - which featured signature, inspired Rod Serling writing - won CBS to the concept of putting science fiction and fantasy into prime time.