But substitute Silvestre Varela levelled at the death after a subdued Ronaldo delivered a cross into the penalty area to set up a thrilling, and possibly controversial, conclusion to Group G.
All four teams are still in the reckoning with a myriad of potential scenarios, but Portugal can only advance if they beat Ghana and hope the United States v Germany result goes their way. If USA and Germany draw, both will be guaranteed of progressing to the last 16.
Despite needing only a draw against Germany - his home country and the team he once coached with current boss Joachim Loew as his assistant - Klinsmann dismissed suggestions he could play for a point.
"The US are known to give everything in every single game," Klinsmann said. "We have that fighting spirit and determination to try to win every game and therefore we will go for a win against Germany."
He said he did not expect a call from Loew, who was assistant coach when Klinsmann led his country to third place as hosts at the 2006 World Cup. "There will be no such call. We are good friends but we are both here to do our jobs. There is no time right now to have friendship calls."
WHAT HAS HAPPENED BEFORE
In Italy they call it a 'biscotti' - a result which ensures both teams achieve their goal, and Italy were certainly crying foul at Euro 2004 when they were eliminated from the group stage after Denmark and Sweden drew 2-2 - a result which was widely known before kick-off would see both teams progress.
There is absolutely no suggestion of foul play from either side of course, but it didn't go down well in Italy - particularly as Scandinavian fans of both persuasions seemed keen to rub it in.
A rather more nefarious incident was the disgraceful contest at the 1982 World Cup which saw West Germany and Austria progress at the expense of an exciting Algeria side.
A one- or two-goal win for West Germany would send both teams into the knockout rounds and lo and behold, after Horst Hrubesch's early opener, neither side mustered a shot or barely as much as a tackle as they passed the ball around for the remaining 80 minutes.
Spanish newspapers dubbed it 'El Anschluss' - referencing Adolf Hitler's annexation of Austria in 1938. It was this game which forced FIFA to ensure that final group games are played simultaneously.
To suggest any form of collusion is an affront to the professionalism of both sides. The match may well end in a draw, but it will not be pre-arranged. Just look at how USA scored two injury-time goals against Panama in qualifying to win 3-2 and prevent their great rivals Mexico from being eliminated from the World Cup.
Just hours after rather more serious accusations regarding possible match-fixing and the Ghanaian FA - relating to theoretical friendlies, not the World Cup itself - debates over a favourable draw between Germany and USA have to be taken light-heartedly.
WHAT PAULO BENTO, PORTUGAL COACH, SAID
"In my entire career as a player and coach, I have never been suspicious about my colleagues playing for a draw. Our obligation is to beat Ghana and although our chances are slim even if we do, we will maintain our professional standards until the very last minute."
Groups A and B come to a conclusion this evening. Brazil, Mexico and Croatia are aiming to secure qualification in the former (at 5pm) while Netherlands and Chile are playing off for top spot in the latter (at 9pm). Get all the vital information in our in-depth previews below.
- Sports & Recreation
- West Germany