Portugal boss Roberto Martinez unmoved by lacklustre D.R. Congo outcome

Teams such as Spain and Argentina had experienced difficult opening World Cup matches before going on to win football's premier tournament, he noted, and it was vital that his players reflected on the game, took lessons on board and moved forward.

"We certainly need to get better. We must be highly self-critical," Martinez said. "Our duty here, I believe, is to evaluate this match, be self-critical and that is the fundamental point ... the World Cup is like that. We continue our efforts.

"I saw that the players' attitude was outstanding first and foremost, and I have faith in what we can achieve."

Among the pre-tournament favourites, Portugal made progress within six minutes thanks to a Joao Neves header but never discovered their rhythm, despite almost 70% possession and a side full of star names that appeared out of sorts, including Cristiano Ronaldo.

It was D.R. Congo who excelled in their first World Cup since 1974, absorbing the pressure and equalising in first-half stoppage time when the unmarked Yoane Wissa headed home a cross, triggering wild celebrations at the Houston Stadium.

No room for sentiment

Martinez said his team started well but the early lead proved to be counterproductive, with his side playing possession football fruitlessly and showing a fear of losing the match rather than attempting to win it.

"We scored at a moment when normally the emotions really help to sustain that momentum and try to score that second goal, but it actually had the opposite effect for us," he said.

"We tried to stick to ball possession, we could not get into the box and we gave Congo an opportunity to regroup and launch counter-attacks.

"But we also have to learn that our style of play and our responsibility really is to attain the highest level possible," he added.

Martinez also cautioned that the players must not become too excited when they are in the lead.

Portugal next play on Tuesday against Uzbekistan, who face Colombia later on Wednesday in the other Group K match.

Martinez praised D.R. Congo, who he said had a good game plan and played as if they were in a major final.

"They were intense, confident. They played like a big final in a major tournament and that shows incredible character," he said.

"We knew that Congo could do that. It was not a surprise."