Portugal captain Cristiano Ronaldo believes his side's bold performance on a difficult pitch in Zenica last week will inspire them to overpower Bosnia at home on Tuesday and qualify for Euro 2012.

Friday's scoreless draw left the two-legged playoff wide open but the Portuguese are confident they will make the most of home advantage after the Bilino Polje stadium's swampy pitch stopped them converting their control of the match into a win.

"That wasn't grass, we played on a vegetable patch. It was very difficult and still we did well and created chances," Ronaldo said.

The world's most expensive player, who last week picked up his second Golden Boot award as Europe's top scorer, was the most dangerous player of the game but his finishing was hampered by the poor state of the pitch.

"We now have a second chance at home in front of our fans, with a good pitch and have all the conditions to ensure we win," he added. "We have to assume we are favourites and show our superiority -- we are a better team."

Portugal, runners-up at Euro 2004, are on the verge of achieving their seventh consecutive qualification for a major international tournament.

Their hard-working opponents were 12 minutes away from securing a berth in next year's finals when they led France 1-0 in their final group match, but were sent to the playoffs after the hosts' late equaliser.

A scoring draw or a win at the Luz Stadium on Tuesday would send the Bosnians to their first major tournament as an independent nation.

The Portuguese had a dismal start to their Euro 2012 campaign but coach Paulo Bento revived the team's hopes, earning five straight wins after he took over in September last year.

Still, needing only a draw to finish top of qualifying Group H and avoid the playoffs, they lost 2-1 to Denmark in their last qualifier to end up second.

"All teams go through different cycles and tough moments but we had a good qualifying (campaign), we simply did not grab that one point in Denmark ... now, I believe we will win," Ronaldo said.

Bosnia, meanwhile, were hoping a better pitch would also work in their favour.

"Maybe the Portuguese think we will be easier opponents on a better surface but we won't. The fact is that we are also looking forward to play on a quality pitch," Bosnia striker Edin Dzeko said.