Since he assisted in the goal, it means that the sub is a good one. See what I mean? You did not spell it out but it is clear to me that you think only Giovinco and Trezeguet can make the difference. The reality is that you are wrong since Grygera was involved in the goal.
Comparing Marchionni and Cristiano Ronaldo isn't stupid. CR7 flops for the national team as much as Marchionni flops for Juventus. His player of the year award is for his 42 goals scored for Manchester United, a team with a strong defence to support his lack of defensive work and great players like Rooney, Scholes and Evra who helped in the attack, thus distracting opposing defenders. He disappears in big matches, rarely tracks back, and missed in the shootout. His dribbling ability is crap compared to the likes of Messi, Ribery and Camoranesi, his free kick-taking ability is nowhere as good as the past greats. If Messi had not been injured so often or if Kaka had not been hampered by the exertions of the past years, Ronaldo would not even be considered. Just look at his performance with the national side where the teamwork is not good and the defence is creaky. How many times did he make the difference? His relatively poor technique is clearly exposed.
This isn't hockey, where a second player can get an assist on a goal despite his pass being tipped. The assist on that goal was by Nedved. Grygera put a ball into the middle that was off the mark, deflected, and the only reason the play worked out was because of a brilliant touch by Pavel and a perfectly composed chip by Vincenzo. C'mon now... let's not give Grygera props because he completely lucked out and two other players made brilliant plays.
Beyond that, what about Genoa's third goal? I easily could be wrong about this, as I was watching a totally shit internet stream, but I am fairly sure that Grygera blew that offside trap and was one of possibly 2 players keeping Rossi onside... which, if I'm correct, would be so fucking typical. I could easily be wrong, but at the time, I thought that is what I saw. Anyways, regardless of whether that mistake actually was his or not, there is NO player on our team that has made as many costly mistakes this season as Grygera. RB is our biggest hole right now, IMO. Anyways, I digress.
Regarding Giovinco and Trezeguet - absofuckinglutely I believe in them to make the difference. Way, way, way more than I believe in Marchionni. Infinitely more. That's because David is one of our champions, a phenomenal finisher, who has consistently made a difference for this team in the past. Giovinco has demonstrated that he is lightning quick, an excellent passer, a tremendous dribbler, and in general an extremely dangerous offensive player who has clearly begun to demonstrate his true worth. Since the Chelsea game, he has EASILY been one of our best players. Marchionni offers none of those qualities, and in a situation where we are desperate for goals, I can't see how anyone can justify selecting Marchionni (easily one of our worst) over Seba.
The bottom line is that regardless of being a man short, if a team is down a goal in a game that is crucial to the season (and one could basically make a case that at 2-1 we were 2 goals short, considering that we effectively knew going in that a win was required to keep Inter even remotely in our sights), there's no way in hell that a coach should sub in a team's 2 WORST players. Especially considering the alternative options previously noted.
As for Ronaldo, I really dislike him, and I basically never defend this player. However, for you to compare him to Marchionni is absolutely ridiculous. The fact that you're trying to rationalize such a ludicrous statement by comparing Ronaldo's technical abilities to a bunch of incredibly talented players NOT named Marchionni is possibly the most bizarre thing that I have ever read on this forum.
Clearly Ronaldo receives a lot of support, but it's also clear that Marchionni wouldn't even crack ManUre's squad at the moment.
Oh, and despite his questionable performance in some big games, and despite the fact that he inexcusably missed that penalty, do you remember who scored Manchester United's goal from open play in the CL final? Even if you say that Scholes cross was sublime, it was still Ronaldo who buried a fantastic header (if memory serves me, the cross was by Scholesy). In total, we're talking about a player who scored 42 times in 49 games, and had an incredibly 'poor' mark of 8 goals in 11 - clearly meaningless - Champions League matches.