Betfair

"From a betting odds perspective, what is the most unlikely thing to have happened in football?" wondered Paul Griffiths back in 2005.
 
"The longest odds for a single result would either have been:

500-1 USA beat England 1-0 in 1950,

500-1 Hungary beat England 6-3 at Wembley in 1953

500-1 Manchester City's remarkable FA Cup fourth-round replay win at Tottenham back in 2004. Spurs led 3-0, but City – with 10 men – stormed back to win 4-3.

999-1  Back in January, Internazionale trailed Sampdoria 2-0  in the 88th minute  of their Serie A clash. "With maximum odds of 1,000 against (the equivalent of 999-1) available, the price was snapped up by a Berkshire man," says company spokesman, Tony Calvin. "Then Obafemi Martins scored in the 88th minute, before Christian Vieri and Alvaro Recoba won the game for Inter in injury time. The punter had scooped almost a grand for his £1 staked.

 Our previous high was 'only' a winning bet at 550 (549-1) on the draw, when a Cameroon side came back from 5-0 down to finish 5-5 against Portugal at the Under-17 World Championships in 2003."

Argintena

"Inter's 2-0 win over Catania last week kicked off with 13 Argentinians on the pitch
Esteban Cambiasso,
Diego Milito,
Rodrigo Palacio,
Walter Samuel and
Javier Zanetti for Inter,
Sergio Almirón,
Pablo Alvarez,
Mariano Andújar,
Pablo Barrientos,
Gonzalo Bergessio,
Alejandro Gómez,
Mariano Izco,
Nicolás Spolli for Catania),"

writes Todd Ashton. "A further three came on as substitutes (
Ricardo Alvarez for Inter,
 Lucas Castro and
Adrian Ricchiuti for Catania

So of the 27 players used in the match, 16 were born in Argentina and for the last 20 minutes 14 of them were playing together."

Poli II Timisoara

"I was recently digging up the history of many cup tournaments and I found out that in 1980 Real Madrid played their reserve squad in the final of the Copa del Rey," wrote Svilen Tomov last week. "Is this the only occurrence anywhere, or has it happened more than once?"

Not that we know of, Svilen, but there have been a few close misses. First, though, let's take a look at that remarkable cup run of Castilla CF, Real's reserve team. They began with two-leg wins over Extremadura, Alcorcon (who a couple of years ago embarrassed the full Madrid side), and Racing Santander before taking on the big boys of La Liga.

Hércules (who finished 15th in the top flight) were beaten first, then Athletic Bilbao (seventh), Real Sociedad (runners-up) and finally Sporting Gijón (who came third behind Sociedad and Real) in the semi-finals. 

The adventure wasn't over, though. With Real winning the title, Castilla became Spain's entrants in the 1980-81 Cup Winners' Cup, the only reserve side ever to compete in European competition (at least until English sides started fielding theirs in the Uefa Cup). It was a brief but eventful campaign. In the first round they beat a West Ham side including Trevor Brooking et al 3-1 at the Bernabéu, but violence at the game meant the return leg was played behind closed doors. The Hammers won 3-1 in 90 minutes and the 262 spectators who had somehow crept into Upton Park saw David Cross score twice in extra-time to complete his hat-trick and send the English side through 6-4 on aggregate.  

Ajax's second team were just a penalty shootout away from meeting their first XI in the 2001-02 Dutch Cup final, reports Tom Adams on Twitter. Having beaten De Graafschap in the third round, Twente in round four and Telstar in the quarter-finals, Ajax II's cup run came to an end against Utrecht in the last four, 7-6 on penalties after a 2-2 draw. (It was quite a young side that Ajax II had back then: Maarten Stekelenburg, Petri Pasanen, Abubakari Yakubu, Jelle van Damme, Steven Pienaar, Nigel de Jong, Wesley Sneijder, Michael Krohn-Dehli, Cedric van der Gun, Jason Culina, Johnny Heitinga and Tim de Cler all featured at various points in the season).

Austria Vienna had a very similar tale to Ajax in the 2008-09 Austrian Cup, with the reserve team beaten by FC Admira in the semi-finals while the first XI went on to win the tournament.

Also close were Hertha Berlin in the 1992-93 German Cup, but it was the first team that, ahem, let the side down. Hertha were dumped out by Bayer Leverkusen in the round of 16, but their reserve team battled all the way to the final, where they were also beaten by Bayer. 

And also deserving of a mention are Sparta Prague B, who reached the Czech Cup semi-finals in 1970-71 having beaten the Sparta first team in the quarter-finals.