A fresh probe has been launched looking into the process to name the American city as tournament hosts, due to its strong links with sportswear giant Nike.
Despite interest being shown by Gothenburg, Eugene was awarded the rights to host the event without a bidding process taking place.
Lord Coe, who recently stepped down from his £100k-a-year role as Nike ambassador, has come under increasing pressure over the decision, but he claims that it was all done above board.
"First, we've selected cities without bidding cycles before," he is quoted as saying by the Daily Mail. "Second, Eugene was not put forward by the IAAF, it was put forward by United States Track and Field... as the best opportunity in the foreseeable future to get world athletics into the United States."
The 59-year-old athletics supremo also denied suggestions that his decision to quit Nike after a 38-year association with the American firm was linked to the ongoing probes into the awarding of the 2021 Championships.