Total horse-****.
Cup semi finals are big games; league games when you know it's now or never, where a slip pretty much condemns you to being out of the race for Europe etc. These are big games. It's when the pressure is on, and it doesn't have to be the final game of the league campaign, or the Final of a cup competition. Each passing game increases with importance if you're in the mix, and when you get to the semis (some would argue quarters) of a Cup, or you enter the final half a dozen or so league games, they all kind of become cup finals as so much hinges on them.
A cup semi is infinitely more of a pressure game than a 3rd round tie. A league game away at Sunderland is much more of a big game in April than the previous season in October, or against a similar-placed side the same season earlier on. It's all about stepping up to the plate and being able to cope with the pressure when it matters most. As you enter the final stages, every match pretty much takes on the mantle of a big game.
Moyes has played one final (awful), plus a semi against the ****e (repeat), Chelsea in the League Cup (err, recurring theme here), and even in the run-in to finishing 4th in 2005 we pretty much limped over the line. The ****e lost it during that run-in. Fulham away sticks in my memory; it seemed like 10,000 of us down there, a win would almost seal it for us: we were dire, and played with far too much conservative caution and fear. Fortunately, that lot also dropped points at the crucial time.
Moyes has overseen plenty of big games. Even the victory over United in the 2009 semi was turgid and we were taken to penalties by a scratch United eleven. Again, that afternoon had Moyes' big game mentality stamped all over it.