The pot of gold at the end of the Twenty20 rainbow looks a long way off for Sussex now.

Success in the Twenty20 Cup is more important than ever this season with a place in the £2.5m Champions League at stake for the two teams who reach the final.

If Sussex still harbour ambitions to be involved in such a lucrative competition they need to turn things around - and fast.

They have had chances to win all three of their matches so far but have lost them due to some poor decisions and costly mistakes at vital times.

It was a similar story at The Oval today when a fine spell from Dwayne Smith and some tight bowling from Mike Yardy had put Sussex back on top in a game that had appeared to be slipping away from them as they struggled to defend an under-par total of 141.

Abdul Razzaq had different ideas though and emphatically swung the game back in Surrey's favour with four consecutive fours off the unfortunate Robin Martin-Jenkins in the 17th over.

If that was bad, worse was to come as Razzaq launched the next delivery from Martin-Jenkins towards the normally safe hands of Carl Hopkinson on the long-off boundary.

The ball was travelling at a fair pace but it was straight down Hopkinson's throat and yet he somehow let it slip through his fingers and over the rope for six.

If he had held on Surrey would have needed 20 from the last 19 balls with a new man at the crease but instead Razzaq hit the next delivery for another six to make it 28 from the over and the game was effectively in the bag.

It would be wrong to point the finger at Hopkinson though as there were plenty of other areas where Sussex let themselves down.

The Sharks were 54-0 after six overs compared to 53-1 at the same stage against Hampshire on Friday but whereas they went on to make 204 on that occasion this time they lost all momentum once Chris Nash had departed for 52.

In fact they went ten overs without scoring a boundary as Usman Afzaal and Matthew Spriegel once again highlighted the importance of spin as they conceded just 16 runs apiece from their four overs.

Big hitters Dwayne Smith, Matt Prior and Murray Goodwin all failed on a difficult pitch to score on and although frontline batsmen Chris Adams and Mike Yardy were there at the death they only managed five runs from the final over.

With a modest total to defend Sussex could not afford to gift Surrey any runs but they then proceeded to concede 18 in wides, a cardinal sin in this format of the game.

Even then they still looked in with a shout when Smith picked up the wickets of James Benning, Scott Newman and Ali Brown in quick succession but Razzaq ensured they paid the price for their mistakes in the end.

Robinson said: "We were probably ten runs down on a total we would have wanted but it was still competitive because the pitch was difficult for the batsmen to time their shots on.

"It was looking like being another close game but Razzaq has come in and taken the game away from us with some brilliant hitting.

"You never know what might have happened if Carl had held that catch but this format of the game can turn on moments like that.

"We might have lost but we have fought all the way in all three games. We put up another strong performance but it wasn't enough."