Roddick fears he may never win Wimbledon title

Roddick has always believed the faster grass courts of Wimbledon made the tournament his best bet to win another Grand Slam.

But the former US Open champion looks increasingly unlikely to fulfil his dream after yet another early exit from the All England Club.

Although Roddick made the final in 2009 -- losing in five sets to Roger Federer -- the American has now failed to get past the fourth round in three of the last four years.

With age no longer on the 28-year-old's side, he concedes it has occured to him that he may never get to lift the championship trophy.

"Well, sure. You're human. I mean, of course it does. You may never get your favourite job either," Roddick said.

"I haven't played well this year for sure. I don't think I've played my best since probably April of last year.

"I've been up against some stuff. But it has to get better, there's no doubt.

"You keep moving forward until you decide to stop. At this point I've not decided to stop so I'll keep moving forward."

Although Roddick was hugely disappointed not to make the second week of his favourite Grand Slam, he insisted he wasn't as devastated as when he lost in the second round against Janko Tipsaveric in 2008 and Lu Yen-Hsun in the fourth round last year.

"It's easier for me to walk out of here and move forward with that than, let's say, 2008 where I lost to Tipsarevic and I felt like I completely choked or last year where I had a million opportunities and gave it away," Roddick said.

"He played an outstanding match. He served about as well as someone has against me.

"The stuff that's enabled me to beat him seven times, making passing shots under duress, making him play defence on his forehand, he did well today.

"The thing you guys have to understand is there's no script. Some days you're going to play well and lose, and some days you're going to play like crap and win."

Roddick had won all seven of his previous seven meetings with Lopez, but the last of those encounters on grass at Queen's earlier this month suggested the eighth seed wouldn't have it all his own way on Centre Court.

It had taken Roddick three tough sets to see off Lopez at the Wimbledon warm-up event and this time the Spaniard was finally able to break his losing run.

Lopez, twice a Wimbledon quarter-finalist, served brilliantly and stopped Roddick establishing his power-game as the world number 44 secured a tie against Gael Monfils or Lukasz Kubot in the last 16.

The Spaniard once ended Tim Henman's Wimbledon career in 2007, but he described the win over Roddick as the best of his career.

"It's definitely great win for me. I beat a couple of great players in Wimbledon in the last 10 years. But to beat Andy in this court is very special, of course. I would say maybe the best probably," said Lopez who sent 57 winners past the American.

"We played recently in Queen's. I lost it, but I played great. So I knew if I played the same way I would have my chances.

"When you play Andy Roddick here, you never expect to win two straight tiebreaks against him. So I'm really happy with my performance. I think the grass, it was always my best surface."