| Fight Name: | Capital Showdown |
| Fight Date: | 10 December 2011 |
| Location: | Convention Center, Washington, D.C. |
| Titles: | WBA and IBF Light Welterweight championships |
| Fighter1: |  Amir Khan |
| Nickname1: | "King Khan" |
| Hometown1: | Bolton, Greater Manchester |
| Purse1: | $1,100,000 |
| Record1: | 26–1 (18 KO) |
| Height1: | 5 ft 8+1/2 in |
| Weight1: | 139 lb |
| Style1: | Orthodox |
| Recognition1: | WBA and IBF Light Welterweight Champion The Ring No. 1 Ranked Light Welterweight |
| Fighter2: |  Lamont Peterson |
| Nickname2: | "Havoc" |
| Hometown2: | Washington, District of Columbia |
| Purse2: | $650,000 |
| Record2: | 29–1–1 (15 KO) |
| Height2: | 5 ft 9 in |
| Weight2: | 140 lb |
| Style2: | Orthodox |
| Recognition2: | IBF No. 1 Ranked Light Welterweight WBA No. 12 Ranked Light Welterweight The Ring No. 6 Ranked Light Welterweight |
| Result: | Peterson defeats Khan via split decision |
Amir Khan vs Lamont Peterson, billed as Capital Showdown, was a boxing match for Khan's WBA (Super) & IBF light welterweight titles.[1] [2] The fight took place in the Convention Center in Washington, D.C., United States, on 10 December 2011. Khan was making the first defense of his IBF belt against his mandatory challenger.[3]
Golden Boy Promotions CEO Richard Schaefer announced in a conference in London to officially kick off "Capital Showdown: Khan vs. Peterson".
The tour touts an HBO-televised bout featuring WBA (Super) & IBF light welterweight champion Amir Khan of Bolton, England, in the first defense of his IBF belt against mandatory challenger Lamont Peterson of Washington, D.C., which was slated for December 10 in Peterson's home town.
Khan had won eight consecutive fights, four of them by knockout. Peterson won an IBF eliminator with a 12th-round stoppage of Victor Cayo (26-2, 18 KOs) in July, earning the organization's No. 1 contender status and the right to challenge Khan.
The fight was fought in front of a packed house at the Convention Center, with an announced audience of 8,647. After an extremely close, evenly matched fight for 12 rounds, the heavily pro-Peterson crowd was thrilled by the split decision announced in Peterson's favor. Khan scored a knockdown in the first round, but was penalized twice by referee Joe Cooper, once for excessive shoving with the forearm and later for hitting on the break. The points proved to be the difference between the two scorecards that favored Peterson.[4]
HBO's unofficial scorer Harold Lederman had Khan the winner 113–112 while ESPN had it 114–111 for Khan.
After the bout Khan, complained about the referee[5] and made accusations of impropriety that the judges' scorecards had been "interfered with"[6] by a man at ringside who celebrated with Peterson after the decision. This man was later identified as Mustafa Ameen, a figure affiliated with the IBF but who had no apparent reason to be involved. Khan's camp launched an appeal with the IBF in December, principally on the grounds of "miscalculation of the scoring," and "inappropriate conduct by officials" and in January 2012, after reviewing the evidence, the WBA ordered a rematch.[7]
Despite rumours, on 3 March 2012, the WBA did not reinstate Khan as the WBA Super Light-welterweight Champion.[8]
However, on 8 May 2012, it emerged that Peterson failed a drug test, testing positive for a banned substance thought to be synthetic testosterone.[9] [10] The Nevada Athletic Commission denied Peterson a licence to box, and the fight was cancelled. The WBA reinstated Khan as champion, although the IBF did not.[11] [12]
Confirmed bouts:[13]
Seth Mitchell vs. 
Timur Ibragimov Anthony Peterson vs. 
Daniel Attah
Fernando Guerrero vs. Robert Kliewer Ramesis Gil Dusty Harrison vs. Terrell Davis Thomas Williams Jr. vs. Reynaldo Rodriguez Terron Grant vs. Dashawn Autry Joshua Davis vs. Christopher Russell| align=center | Country | align=center | Broadcaster |
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| Main Event | |||
| Sport 1 | |||
| Canal+ | |||
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| AKTV | |||
| Polsat Sport | |||
| Sport TV | |||
| Sport.ro | |||
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| NTV Plus | |||
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| Sky Sports | |||
| HBO |