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The ATP Challenger Tour, known until the end of 2008 as the ATP Challenger Series, is a series of international men's professional tennis tournaments. The top tier of men's tennis is the ATP World Tour, Challenger Tour events are the second highest level of competition, and the Futures tournaments on the ITF Men's Circuit are the third and final tier of international professional competition. The ATP Challenger Tour is administered by the Association of Tennis Professionals. Players who succeed on the ATP Challenger Tour earn sufficient ranking points to become eligible for main draw or qualifying draw entry at ATP World Tour tournaments. Players on the Challenge Tour are either young players, those who fail to qualify for ATP events, or former ATP winners looking to get back into the big tour.

The first challenger events were held in 1978, with eighteen events taking place. Two were held on the week beginning January 8, one in Auckland and another in Hobart. The next events were held one at a time beginning June 18 and ending August 18 in the following U.S. locations, in order: Shreveport, Birmingham, Asheville, Raleigh, Hilton Head, Virginia Beach, Wall, Cape Cod, and Lancaster.

Events continued after a one-month hiatus with two begun September 24 and 25, one in Tinton Falls, New Jersey and in Lincoln, Nebraska respectively. The following week saw one event played, in Salt Lake City, then two played simultaneously in Tel Aviv and San Ramon, California, then one played the following week in Pasadena. A final event was played a month later in Kyoto. In comparison, the 2008 schedule saw 178 events played in more than 40 countries.

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