The hosts took a shock lead on the half-hour when Stanislav Manolev's 35-yard strike rocketed past Gianluigi Buffon but Pablo Osvaldo's scored twice in three minutes, both from close range, to put the Azzurri ahead at the interval.
But Italy were pegged back as Milanov fired high into the net from Iliyan Mitsanski's cross to ensure a share of the spoils in encounter in Group B, where Armenia went top after Artur Sarkisov's 70th-minute strike gave them a 1-0 win over Malta.
Robin van Persie scored the opener as Netherlands began their campaign with a 2-0 victory over Turkey in Group D.
The Manchester United striker opened the scoring in the 16th minute and Luciano Narsingh added a second in stoppage time as the Dutch registered a morale-boosting victory following their poor Euro 2012 showing.
Hungary showed they will be tough challengers for the Dutch after they breezed past Andorra 5-0.
Strikes from Roland Juhasz, Zoltan Gera's penalty, Adam Szalai, Tamas Priskin and Vladimir Koman sealed a comfortable victory, while goals from Gabriel Torje and Ciprian Marica gave Romania a 2-0 win over Estonia.
England launched their World Cup qualifying campaign with a 5-0 Group H win in Moldova, to record their biggest away win since 1993.
Frank Lampard scored twice to provided the perfect answer to questions about his age, with Jermain Defoe, James Milner and a deflected Leighton Baines free-kick underlining England's overwhelming superiority.
Elsewhere in the group, Montenegro and Poland drew 2-2 in a fiery encounter that saw both teams reduced to 10 men.
Abou Diaby scored the only goal as France edged past Finland in Group I, while Georgia got their campaign off to a winning start as a fine second-half goal from Tornike Okriashvili saw off the challenge of Belarus.
Germany began their qualifiers with a routine 3-0 Group C win over the Faroe Islands.
Mario Gotze broke the deadlock in the 28th minute before Mesut Ozil's second-half brace sealed a comfortable, if unspectacular, victory.
Last-gasp goals from Robbie Keane and Kevin Doyle ensured the Republic of Ireland avoided embarrassment after they came from behind to beat Kazakhstan 2-1.
Giovanni Trapattoni's men looked set for an embarrassing defeat when Kairat Nurdauletov glanced home after an insipid first-half performance from the visitors until Keane's penalty and Doyle's strike gave the visitors a hard-fought win.
In Group A, defensive duo Vincent Kompany and Jan Vertonghen gave Belgium a 2-0 win over Wales, whose early good work was undone when James Collins was sent off in the 25th minute.
Nikica Jelavic's opportunist 68th-minute header got Igor Stimac's reign as Croatia coach off to a winning start against Macedonia.
Cristiano Ronaldo was on song but Portugal only edged past minnows Luxembourg 2-1 in Group F.
The Portugal midfielder drew his side level just before the half-hour mark after Daniel Da Mota Alves gave Luxembourg the lead, before he made a nuisance of himself in a top-class performance which saw Helder Postiga's strike earn the visitors a well deserved win.
Northern Ireland's qualifying campaign got off to a losing start as goals from Viktor Fayzulin and Roman Shirokov gave Fabio Capello's Russia three points in Moscow, while Israel were forced to settle for a 1-1 draw at Azerbaijan.
Granit Xhaka and Gokhan Inler gave Switzerland, who had captain Tranquillo Barnetta sent off, a 2-0 win at Slovenia, while goals in either half from Kari Arnason and Alfred Finnbogason gave Iceland a 2-0 win over Norway, and Albania beat Cyprus 3-1.
In Group G, Greece came from behind to beat Latvia 2-1, Edin Dzeko and Vedad Ibisevic scored a hat-trick apiece as Bosnia-Herzegovina thrashed Liechtenstein 8-1 and Lithuania and Slovakia played out a 1-1 draw.
Friday's 2014 FIFA World Cup (UEFA) Qualifying Results