* Tipsarevic pulls out of Davis Cup final with heel injury
* Inexperienced Lajovic steps in
* Djokovic likely to play in Saturday's doubles (Adds quotes, detail, byline)
By Zoran Mirosavljevic
BELGRADE, Nov 14 (Reuters) - Serbia's world number two Novak Djokovic will face his toughest Davis Cup weekend after team mate Janko Tipsarevic was forced to pull out of the 2013 final against holders Czech Republic with a heel injury.
With Viktor Troicki suspended after missing a blood test, Djokovic is expected to shoulder the burden for the 2010 winners as he will in all likelihood join forces with Nenad Zimonjic in Saturday's doubles after playing Radek Stepanek in the opening singles rubber on Friday.
Dusan Lajovic, nominated as Tipsarevic's replacement, takes on Tomas Berdych in Friday's other singles and Djokovic acknowledged the 23-year old from Belgrade's nondescript suburb of Stara Pazova will need all the help he can get.
"It's a pity Tipsarevic can't play but his support from the sidelines will mean a lot to us, most of all to Lajovic who now has the opportunity to show his potential on the big stage," Djokovic told a news conference after Thursday's draw.
"What we have to do is take the pressure off him and make sure he doesn't suffer from stage fright, because no one expects him to beat Berdych. We all know that would mean asking a lot.
"If I beat Stepanek, he should get a confidence boost from Serbia being 1-0 up in the tie and with the vociferous support from 18,000 fans in the Kombank Arena, anything can happen."
Lajovic's only Davis Cup appearance was a dead rubber win over Swede Filip Prpic in their 2012 first-round tie and the world number 117 said he relished the unexpected chance to be in the spotlight.
Asked how he felt about being the star of Thursday's news conference instead of Djokovic, Lajovic said: "I'd much rather be the star of the final press conference on Sunday because this is going to be the biggest weekend of my career.
"I was very excited when I got the news this morning and Djokovic's advice before the tie starts will be priceless, just being around him is a huge incentive to work harder than ever."
Serbia's Ilija Bozoljac has been nominated to play alongside veteran Zimonjic in Saturday's doubles against Jan Hajek and Lukas Rosol, but there is little doubt that both team captains will exercise their right to reshuffle the side.
With Djokovic in devastating form having won 22 matches in a row and four tournaments after losing the U.S. Open final to Rafa Nadal in September, he appears to be the right choice to team up with Zimonjic.
"We are certainly looking at that option because one of Djokovic's strengths is the ability to adapt to any situation," said Serbia team captain Bogdan Obradovic.
"But we will make that decision after Friday's singles, depending on the result and how the players feel."
Obradovic's Czech counterpart Vladimir Safarik, deputising for the ill Jaroslav Navratil, is even less likely to stick to his nomination of Jan Hajek and Lukas Rosol, with Berdych and Stepanek the obvious first choice having won 13 of their 14 Davis Cup doubles as a pair. (Writing by Zoran Milosavljevic; Editing by Amlan Chakraborty and Alison Wildey)