Defending World Cup holders Italy will anxiously await test results on goalkeeper Gianluigi Buffon after he was forced off with a nerve injury during the 1-1 draw with Paraguay.

Buffon, the long-standing Azzurri number one and arguably still the world's best goalkeeper, suffered a sciatic twinge during the warm-up in Cape Town last night.

Buffon defied the team doctor's advice to start the match but had to be replaced by Cagliari's Federico Marchetti at half-time.

While the player hopes he will be fit to face New Zealand in Italy's second Group F game on Sunday, team doctor Enrico Castellacci is more cautious.

"The coach subbed me because I had problems in my leg," the Juventus goalkeeper revealed.

"I was not very good during the warm-up, my leg was hurting.

"The doctor suggested before the match that I was replaced for one of the other goalkeepers.

"I hope this injury will be better when we play New Zealand."

Team doctor Castellacci said after the match: "It's a sciatic nerve problem he felt during the warm-up. He couldn't really go and play.

"On Tuesday morning we will decide what we have to do with him. We will look at exams and therapies needed for this injury.

"We don't know the number of days he will be out for. We need to look at what special medical machinery we need for this kind of injury."

As for the match itself, Buffon said: "We had the possession but Paraguay had some luck. I think 2-1 would have been a better reflection for us.

"We tried to keep it at 1-1 at first and I think it's a good result for the team and New Zealand is another match."

Having played well in the first half at Green Point Stadium, the defending champions were shocked when Paraguay defender Antolin Alcaraz rose to head home a 39th-minute free-kick.

Italy's blushes were spared to some extent, however, as Daniele De Rossi slid in to punish a mistake by Paraguay goalkeeper Justo Villar after 63 minutes and take a point from the match.

Buffon's injury did give Marchetti his big chance on the world stage, although in truth the highly-rated Cagliari man had little to do in the second half.

"It's my first World Cup and I was very happy to play," he said afterwards. "It was a great emotion for me."

He added: "It was really exciting, although at the same time I'm sorry for Gigi. Before I came on he calmed me down and encouraged me, and that was really nice coming from such a great champion like him.

"I think we needed the second goal because we played very well second half and we need to forget the first half.

"Italy is known for improving match after match."

Paraguay striker Lucas Barrios believes the result - and the performance - against the champions can spur Gerardo Martino's side on in the group.

"I'm happy with this result, a draw with the world champions is very good even considering we had the lead," he said.

"We have more matches to come. This gives us a lot more confidence.

"We wanted to play at the same level as Italy, we didn't want to just defend. So we're happy even though we could have won the game."