"Pressure? What pressure?," asks Serena Williams at Wimbledon

Serena Williams gave little away on Sunday as she assessed her chances of retaining her Wimbledon title -- and dismissed suggestions that she is under any pressure.

The 34-year-old American has not struck a ball competitively since losing to Spain's Garbine Muguruza in the French Open final on June 4 - a defeat that frustrated her hopes of matching Steffi Graf's professional era record of 22 grand slam titles.

Considering she also fell at the final hurdle in Australia against Angelique Kerber and went out of the U.S. Open semi-finals last year when two wins away from a calendar grand slam, Williams would be forgiven for feeling a little edgy.

But she was hiding any tension well to the world's media on the eve of the tournament.

"I don't feel any pressure. I feel good and confident," she said at the All England Club where she has won six singles titles, one more than her older sister Venus.

Williams never feels the need to play grasscourt warm-up tournaments, preferring instead to hit on the hardcourts back home before arriving in the week before the tournament. It is a tried and tested formula.

"I got here, I think, on Monday. So I've had a lot of time on the grass. I did the same preparation, and it seems to work," said Williams, who starts her campaign on Tuesday against 148th ranked Swiss qualifier Amra Sadikovic.

Asked if she has found out anything about Sadikovic, she said: "Not yet. But normally, my coach obviously does a lot of research, or the most that he can, then we go from there.

"Honestly, it doesn't matter who I play.  It doesn't matter to me."

While her approach is nonchalant, there are some who feel Williams' struggle to match Graf's record is playing on her mind.

"It's not easy to try to do what she's doing, to make history at this stage," three-times Wimbledon champion John McEnroe said in the build-up.

Another former champion Chris Evert reckons Williams is still the favourite but says other players are seeing a chink in her armour as she gets older.

"In the last few years, she's been good enough at 60 percent to 70 percent to win matches," said the American, who will be commentating for the ESPN network along with McEnroe.

"Now I don't think it's going to win matches for her. The competition has gotten better. They're less intimidated by her. They know she's human. They've seen a couple of bad losses."