Portugal coach Paulo Bento admits that keeping a first-leg clean sheet was vital to the 4-2 aggregate win over Sweden which saw them qualify for the World Cup.

Portugal manager Paulo Bento has identified their preventing Sweden from scoring an away goal in the first leg as crucial to their World Cup qualifying playoff win.

The Selecao kept a clean sheet on Friday, which meant that Cristiano Ronaldo's second-half hat-trick on Tuesday night was enough for them to comfortably secure a place at Brazil 2014.

Bento has admitted that shutting out Sweden in Lisbon was a big part of Portugal's approach to the tie, and has applauded his country's players for progressing to their eighth straight major tournament.

"Qualification was fair, and we have to enjoy the moment," Bento told reporters. "We must also congratulate all the players who were not involved in the game and those who took part in the process of us reaching the World Cup.

"Not conceding goals in the first game was a big part of our strategy. In the first-half tonight we were not as we could have been but we still dominated - but we have to remember the players were under a great deal of pressure.

"Since 2000, Portugal has made every finals without a break and this generation needs to be congratulated."

Ronaldo, who also scored in the first leg, has insisted that Portugal "deserved" their aggregate victory.