Scholes' goals may not be enough for United
Despite being favourites at odds of 11/10, Manchester United face an extremely difficult task as they try to bring an end to Porto's unbeaten run.
United may well still be reeling that Porto had the cheek to turn up to Old Trafford, score first, and then grab a late equaliser which you can be sure was not in Sir Alex Ferguson's game plan.
Porto are as long as 5/2 in the betting to finish the job off and defeat United at the Estadio do Dragao with the draw at 23/10 which would send Porto thorough thanks to the away goals rule.
There is no doubt Jesualdo Ferreira will have his team pumped full of belief that they can do this as they have not only never lost to Man Utd at home in three encounters, but they have never lost a home European match to an English side.
Add to this Porto are unbeaten in 20 games, and they have two away goals already and you see the enormity of United's task.
The Red Devils do thrive under pressure and Fergie has been here and done it all before and he will know what needs to be done to secure the win or high draw they need.
The 2-2 score line in the last game shocked many, and the same result at odds of 14/1 would take the game to extra time. Any lesser draw and United are out, therefore a 1-0 or 2-0 win to the away side available at 11/2 and 6/1 respectively and would to the job.
Porto will be desperate to not throw lose their away goal advantage which makes scores like 1-0 or 2-1 to Porto possible at odds of 13/2 and 11/1 respectively.
If Man Utd are to really rattle Porto and in turn sweep them aside, they will need to come absolutely flying from the kick-off much like the Portuguese side did at Old Trafford.
Should they get an early goal then you can quite easily see them going on and winning it, or at least doing enough to qualify.
If this is the case a double result like Man Utd/Man Utd at 11/5 may appeal with Man Utd/draw at 14/1.
It could of course be an extremely tight affair with both teams cancelling each other out until later on. In which case draw/Man Utd or draw/Porto could be for you at 4/1 and 6/1 respectively.
Cristian Rodriguez who opened the scoring last time can be backed at odds of 10/1 to do so again or 7/2 to score anytime, while Lucho Gonzalez who score the equaliser is 10/3 to find the back of the net this time around.
Lisandro Lopez and Hulk are 13/2 and 7/1 respectively to get the home side off to a flyer yet again and seriously dent United's hope of qualification.
One thing Man Utd do possess is a deluge of striking talent. Wayne Rooney and Carlos Tevez got on the score sheet in the first leg and are both 13/2 to open the scoring this time, while Cristiano Ronaldo is 5/1.
Dimitar Berbatov may get a run out at some point also at 7/1 for first or last goal, while man-of-the-moment Federico Macheda who has score the last goal twice in two appearances can be backed at 8/1 to do so again.
Some value could be found in Paul Scholes to score anytime at odds of 6/1, who scored in 2004 when these two sides met, and managed to bag a goal at the weekend also which means he could well add to his phenomenal Champions League goal tally.
United's recent habit of leaking goals is a cause for concern, but nearly every time they have had the quality to come back at the death.
This reiterates the points that you can never write The Red Devils off and there is no doubt they will battle on right to the end with Fergie still after an astonishing five trophies.
Porto are very tough to beat at home as their record shows and they concede very few at all.
While Man Utd are different quality to any other team in the Super Liga, Porto are well organised, and if they don't sit back and take the game to United, they stand a great chance of causing the upset of the round.
Paul Scholes to score anytime - 6/1