A No. 1 country record isn't anything new to superstar Tim McGraw - but a No. 1 on the Top 40 chart is. Tim's duet with rapper Nelly, "Over And Over," jumped quickly from No. 7 to the top spot last week, according to Billboard. The trade magazine reported that the leap was "the largest position jump to number one and also ties with Whitney Houston and Mariah Carey for quickest ascent to number one." Additionally, the song went to No. 1 within four weeks of its radio release. "Over And Over" is Nelly's fourth chart topper, which gives him the most by a male artist in the Top 40 format and ties him for most No. 1s overall with Mariah Carey, Avril Lavigne, Jennifer Lopez, Christina Aguilera and Alanis Morissette. But Tim is the first country artist to hold the No. 1 position at the Mainstream Top 40 format.