Lee Westwood believes he is finally approaching the form which saw him become world number one, despite arriving at the year's first major championship 37th in the rankings.

Westwood overtook Tiger Woods at the end of October 2010 and held top spot for a total of 22 weeks in two spells before losing it to fellow Englishman Luke Donald at the end of May 2011.

The 40-year-old has slowly slid down the rankings ever since and failed to win a tournament in 2013, most notably finishing third in the Open Championship at Muirfield after taking a two-shot lead into the final round.

He split from coach Sean Foley - who also works with the likes of Woods and US Open champion Justin Rose - at the end of last year after just seven months together, but hopes new coach Mike Walker and old caddie Billy Foster can help rediscover the long game which had always been his biggest asset.

"My game is really good and Thursday's round was definitely the best I have played tee to green in two years," Westwood said after finishing 17th in last week's Shell Houston Open.

"I'm just pleased to be starting to hit the ball good again because I have been struggling for about a year to a year and a half now.

"I'm hitting the ball very well at the moment and that's important going into any major."

Westwood insists there is no need to panic over his world ranking, especially having previously recovered from a dramatic loss of form a decade ago which saw him slip outside the top 250.

And he is relishing contesting the US Masters at Augusta National, where he was second in 2010, 11th in 2011, third in 2012 and eighth last year.

"I first went there in 1997 so I know the course very well," Westwood added. "I'm excited to be going back.

"It's nice that it has come around again because it is such a long time since the US PGA Championship, and the fact there are only four majors a year.

"I feel when I do drive up to the front gates I know the place very well and it's a golf course where I can walk onto the first tee feeling comfortable with where I am. That's shown in my results in recent years."

The chances of Westwood winning a first major title at the 64th attempt have been boosted by the absence of four-time champion Woods, who withdrew last week having undergone surgery on a pinched nerve in his back.

But with favourite Rory McIlroy coming into form at the right time with a closing 65 in Houston - where Sergio Garcia also finished third - Westwood does not believe Woods' absence has changed the goalposts.

"No, not really," Westwood added. "He's never worried me. It will be interesting he's not playing but then there are so many other good players who can win."

Meanwhile, just two hours of practice was possible on Monday before players, and thousands of disappointed spectators, were forced to leave Augusta National due to an approaching thunderstorm.

The bad weather arrived earlier than previously forecast and led to an announcement at 10am asking spectators to leave the grounds and seek shelter.

Tournament officials then announced at lunchtime that the gates would remain closed for the rest of the day, the first time that had happened since the same day in 2003.

Spectators will receive refunds in May and be guaranteed the opportunity to purchase tickets for practice rounds in 2015.

Augusta National chairman Billy Payne said: "We are disappointed that our patrons could not enjoy today's practice round, however, safety must be our first concern. We look forward to seeing these patrons next year."