After Andrea Pirlo had put Marcelo Lippi's team in front from the spot in the first half, Sampdoria striker Pazzini came on as a second-half substitute and found the back of the net in the 72nd minute.

The Italians now lead Group Eight on 13 points - two clear of Wednesday's opponents Republic of Ireland, who were held to a 1-1 draw by Bulgaria.

Hosts Montenegro were without suspended striker Mirko Vucinic, who plies his trade in Italy with Roma, but nevertheless started strong.

Italy goalkeeper Gianluigi Buffon was forced to come off his line to anticipate Simon Vukcevic, who was ready to fire home.

Lippi was forced to make his first substitution in the ninth minute with Pepe replacing Antonio Di Natale, who sustained a left knee injury.

Italy enjoyed a lot of possession but did not have to work too hard for the opening goal 11 minutes into the contest.

The referee pointed to the spot after Radoslav Batak's handled Pirlo's cross.

Pirlo made no mistake with the penalty kick, firing straight down the middle of Vukasin Poleksic's goal.

The Azzurri continued to surge forward and could have doubled their lead soon after when Vincenzo Iaquinta headed over Fabio Quagliarella's right-wing cross.

At the other end, Nikola Dricic's free-kick went way off target as the hosts battled to get back on terms.

Midway through the first half, Italy missed a golden chance to extend their lead.

Daniele De Rossi's clever assist sliced Montenegro's defence wide open and found Pepe, who failed to beat Poleksic in a one-on-one situation.

Full-backs Gianluca Zambrotta and Fabio Grosso caused Montenegro problems with their strong running but the hosts were able to get forward occasionally.

Stevan Jovetic forced a save from Buffon with a dipping shot from 25 yards.

On the half-hour mark, Vukcevic twice had the chance to level the score. His opening strike took a deflection and went off target while shortly after, his long-range effort went high over the bar.

Five minutes before the break, Pepe's central header from Grosso's cross was saved by Poleksic.

Italy picked up where they left off and Iaquinta should have made it 2-0 early in the second half.

The Juventus forward got behind Pepe's assist but made a mess of a header from close range.

Iaquinta's mistake could have proved costly for the Azzurri had Radomir Djalovic's close-range header not going inches wide of the far post soon after.

In the 67th minute, Djalovic was allowed to charge in on goal but Buffon thrust out a hand to keep out the angled shot.

Shortly after, Pazzini wasted a great chance with his close-range effort saved by the keeper.

But Pazzini made no mistake moments later as he latched onto Pepe's perfect pass to head past Poleksic from close-range.

Winless Montenegro pressed forward in the last stages of the game but the Azzurri held on for the victory.