Carlos Checa's defence of his World Superbike Championship crown continues to stall after the reigning champion followed up his dominant victory around Miller Motorsports Park in race one with a costly DNF in race two.

The Spaniard was an example of consistency on his way to the 2011 crown with Althea Ducati, but three non-scores had already served to negate his two race wins coming to the United States.

Nonetheless, Checa looked to have taken another significant step in the right direction when he cruised to a fairly comfortable third victory of the year in race one, in turn notching up a fifth win in nine starts around the Utah venue.

"Race 1 was a great result, a great race, a great moment! I've always had a great relationship with this track and to win here again is just fantastic, especially after some difficult recent rounds.

"The race wasn't an easy one and Melandri pushed right until the end, I couldn't relax for a second! But I was feeling confident with the tyre that we had chosen and was able to make a great race. I had to work hard through the corners as we seemed to be losing a lot on the straights but I am very happy with the result, and happy for the entire team that has worked so hard this weekend.

However, though a repeat result looked destined in race two as he forged a 1.7secs advantage over the competition after just five laps, Checa's weekend would come to a sudden halt with a crash at Demon.

"In this second race I was pushing, I was feeling confident with the setting but clearly I pushed a bit too hard and lost the front. I went back on track but there was nothing I could do, I'd lost too much ground."

With Checa unable to make the most from his race one triumph, he has now slipped to fifth position in the overall standings, 30 points behind series leader Max Biaggi.