The song retains a narrow lead over Flo Rida and David Guetta's 'Club Can't Handle Me', which stays at number two for a second week.
If the track holds on to number one until Sunday, it will mark the band's first number one single after scoring six top ten hits.
Elsewhere on the singles chart, Eminem and Rihanna are at three with 'Love The Way You Lie', while last week's number one Ne-Yo slips to four with 'Beautiful Monster'.
Tinchy Stryder's 'In My System' is currently at number seven, while further down the chart, Ellie Goulding's 'The Writer' enters at 26.
On the midweek album chart, Eminem climbs back to number one with Recovery, shunting Arcade Fire's The Suburbs down to two.
Lady GaGa's The Fame moves up a place to five after 83 weeks on the chart, while Jason Derulo's self-titled LP jumps two places to eight.
Their official chart positions will be announced this Sunday.
Source: Official Charts Company