Goalless draws with Poland and Macedonia, then a 3-1 home loss at home to Turkey a week before the tournament started hardly inspired confidence.
A 1-0 defeat by Germany in their opening game, in a tough Group B also containing 2010 World Cup finalists Netherlands as well as gritty Denmark, left Bento facing mounting criticism back home but Portugal have rebounded in style.
An out-of-sorts Ronaldo was outshone against the Danes by substitute Silvestre Varela who scored a late goal to secure a 3-2 win, but you cannot keep the world's most expensive player out of the limelight for long.
He ran the Dutch ragged with two goals and only the woodwork denied him more, then against the Czech Republic on Thursday he again had the frustration of hitting the post twice before his superbly-timed jump to meet Joao Moutinho's cross secured a semi-final with France or Spain.
The one goal that separated the Portuguese from the Czechs did not reflect the mastery of Ronaldo and the superior quality of his supporting cast.
Captain Ronaldo is the showman but he cannot do it all by himself, despite at times appearing to be trying to.
The golden generation of Luis Figo, Rui Costa and Deco among others has gone without any silverware - Greece saw to that by stunning the Euro 2004 hosts in a final they seemed destined to win - but talk that Portugal are a one-man team eight years on ignores some talented and important players in Bento's side.
Miguel Veloso sits in front of the back four and is the anchor that allows Moutinho and Raul Meireles, a real driving force of energy, to push forward, while Nani drifts from flank to flank, allowing Ronaldo the freedom to roam.
The fluidity proved too much for the tiring Czechs, although more formidable opponents lie ahead.
"In the semi-finals of a great tournament like this, there is always a great team with different characteristics, players of great quality, and well-drilled organisation. We don't mind who we play," said Bento.
Ronaldo, a player who seemingly delivers week in, week out for Real Madrid, has often failed to hit the heights for Portugal when it matters on the big stage.
Clearly an unhappy and frustrated figure under previous coach Carlos Queiroz at the 2010 World Cup where Portugal lost in the last 16 to Spain, it would seem his moment has now come.