The #1 spot on the pop chart this week will belong to one of the ex-1D boys, the only question is which one. Will Capitol's Niall Horan stay in the #1 spot with "Slow Hands" or will current #2 Liam Payne (Republic) climb up and take the crown with "Strip That Down" f/Quavo? Logic's "1-800-273-8255" f/Alessia Cara & Khalid (Def Jam) is on pace to be the Greatest Gainer of the week, taking a big jump inside the Top 10. P!NK's "What About Us" (RCA) makes the move to Top 15, while Taylor Swift's "Ready For It" (Big Machine/Republic) joins the Top 20. Camila Cabello's "Havana" f/Young Thug (Syco/Epic) looks to join the Top 25. And charting this week will be Ed Sheeran's "Perfect" (Atlantic) and Nick Jonas' "Find You" (Island/Republic).