Emerging from the ashes of an emotional 400m contest, Pavel Maslak became the first three-time winner of the event at these championships.
Spaniard Oscar Husillos was first across the line with a 44.92 championships record but his surprise reign was short-lived following his disqualification for a lane infringement. So was Luguelín Santos, the 2012 Olympic champion who chased him over the entire second lap, paving the way for Maslak's historic triumph following his victories in Sopot in 2014 and Portland two years ago.
The Czech didn't arrive in Birmingham in near the form he exhibited prior to his previous two titles, but fought valiantly in the rounds to earn a spot on the start line this evening.
Maslak clocked a season's best 45.47 to collect the win, well clear of US champion Michael Cherry who clocked 45.84 who took silver. But he wasn't as pleased with this victory as he was with his two others.
"I think the guys were stronger than me and I do not know what went wrong for them," he told post-race interviewers. "They would have beaten me anyway so even if it is gold, it will have a bronze flavour for me."
Deon Lendore of Trinidad and Tobago won the actual battle for bronze, edging Aldrich Bailey Jr. of the US 46.37 to 46.44.
Bob Ramsak for the IAAF
NOTE: Jury of Appeal Decision
RULE 163 (The Race)
3. (a) In all races run in lanes, each athlete shall keep within his allocated lane from start to finish. This shall also apply to any portion of a race run in lanes.
(b) In all races (or any part of races) not run in lanes, an athlete running on a bend, on the outer half of the track as per Rule 163.5(b), or on any curved part of the diversion from the track for the steeplechase water jump, shall not step or run on or inside the kerb or line marking the applicable border (the inside of the track, the outer half of the track, or any curved part of the diversion from the track for the steeplechase water jump).
Except as stated in Rule 163.4, if the Referee is satisfied, on the report of a Judge or Umpire or otherwise, that an athlete has infringed this Rule, he shall be disqualified.
IAAF response to lane infraction disqualifications:
Indoor tracks vary widely and far more than outdoor tracks, particularly on the turns which impacts the centripetal force as athletes move from the banked turns to the flat straight. The DQs have been ratified using video footage of the infringements. Indoor racing is a specialised type of competition and many athletes spend very little time training on indoor tracks. Greater familiarisation of different tracks ahead of competitions could be a way forward in reducing these infringements. We will talk to the athletes and seek their views.