UEFA officials were surprised when Thursday's draw for the Champions League knockout stages produced the exact same results as a test run gave them on Wednesday.
The draw is random, and there's a high number of potential matchups between the 16 teams qualified for the knockout stages. So when a rehearsal for the draw on Wednesday produced a slate featuring showdowns between Real Madrid and Manchester United, AC Milan and Barcelona, and Arsenal and Bayern Munich, they never could have expected the real draw on Thursday at UEFA headquarters in Nyon, Switzerland to produce identical pairings.
It wasn't just a random pairing of teams: eight teams were seeded, with eight teams unseeded, and measures were made to prevent matchups from sides who had played in the group stages, or from the same nation, from having to play in the first round of the knockouts. But the odds of an identical draw were still high enough to make it very unlikely.