The undefeated two-weight champion retained his WBC lightweight belt with a flashy and sometimes wincing performance against a brave challenge from Rees, who showed amazing heart in losing to the superior American.
Rees, 32, started the better of the two, taking the first round – before Broner stepped it up in the second to rock Rees and proceeded to showboat and wind up his punches to show the crowd his full control of the bout.
In the third, Broner’s left hand counters became more prominent as Rees continually pushed forward to try and get in range, and at one point, pinned the Welshman onto ropes in ominous fashion at a possible finish.
A peach of a right hand in fourth put Rees down heavily, although ‘The Rock’ lived up to his name by surviving over a minute and a half of the round, but the end was always near from that point on.
A crunching body shot had Rees down again in the fifth and a debate as to whether the referee has said break before it was thrown would have been academic as Broner pummelled Rees again until Gary Lockett threw the towel in.
Broner now moves to 26-0 and a potential unification with another UK fighter in Ricky Burns this summer as Rees drops his second loss from 40 bouts, but goes away having made a big impression on the US fans.
In chief support, former IBO champion Sakio Bika set up a possible showdown with WBC super-middleweight title holder Andre Ward by scoring a wide points win over unproven Nikola Sjekloca in an uneventful contest.
The 33 year-old had too much in his locker for the Montenegrin, who dropped his first loss in 26 bouts as the judges came back with 120-108, 119-109 and 118-112 scorecards to confirm Bika’s dominance.