Rival jockeys aren’t the only ones glad Joao Moreira is leaving Hong Kong, Jockey Challenge bookmakers must be beside themselves to be seeing the back of the Brazilian.

The moment Moreira arrived in October 2014, the Jockey Challenge changed as a bet as the lightweight began his record-breaking run.

Markets have had to be suspended on many occasions as Moreira, having already opened at short odds, rides the first few winners and leaves the bookmakers with no options.

This season it has been more a case of Moreira and Zac Purton’s dominance strangling markets and eating into the margins on the Jockey Club’s only fixed-odds bet type.

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Outsiders create a bigger profit for the Club when they win and a greater range of winners is probably healthier for turnover as well, something that Moreira and Purton just haven’t allowed much of in recent times.

This season, Purton and Moreira have won 67 of the 86 Jockey Challenges, 11 more than the 56 they won combined last season.

Of late the two riders have been on a tear, winning the Jockey Challenge at 24 of the last 25 fixtures.

The Jockey Challenge market takes on a familiar shape today with Moreira installed $1.65 top pick and Purton a clear second at $2.25.

The leading two riders are the only two in single figures, with Matthew Poon Ming-fai at $15.

Moreira and Purton both have a full book of 11 rides as the battle for the jockeys’ championship reaches its crescendo.

Although Moreira is a great chance of riding more winners than Purton, the magic number is five.

Moreira trails by four (135-131) but the fact Purton has more seconds – the tiebreaker – means the real margin is five.

The key race could be the Class Five opener; if Purton can win on Best Effort it will put pressure on Moreira.

Yet if there is an edge in in-play betting, it could be for Moreira through the middle part of the card.

Races four through seven see Moreira aboard Lightning Steed, Have Fun Together, Picken and Last Kingdom.

Four-all: Zac Purton and Joao Moreira trade blows in titanic battle at Sha Tin

If Moreira can close to within two or three coming to the final four meetings it will make for a thrilling finish.

Moreira takes over on Doctor Geoff as Purton picks Rise High in the Sha Tin Mile Trophy before betting closes.

The final race match-up between Moreira’s Hezthewonforus and Purton’s Solar Patch looks hard to pick.