Something incredible happened for Manchester United fans this weekend. Not only did they get to see their team win, but they saw David Moyes employ different tactics which sought to get the best out of the players he has on offer, rather than trying to squeeze the players into an ill-suited 4-4-2.
Having so far proved to be a big success in the Champions League, finishing top of the group and beating the second-best side in Germany, Bayer Leverkusen, 5-0 along the way, what line-up will Moyes go with against Olympiakos on Tuesday?
United may have no option but to go with the back four that started against Crystal Palace, with Chris Smalling and Patrice Evra lining up either side of Rio Ferdinand and Nemanja Vidic.
Rafael da Silva, Jonny Evans and Phil Jones are alternatives Moyes might have wanted to employ for this game, but all three of them were missing from the squad on Saturday.
Evra was named Man of the Match in that game, though, after winning the penalty for the first goal and crossing the ball for the second, so Moyes will be hoping for more of the same from him on Tuesday night.
On Saturday, Marouane Fellaini played his first game for United since the defeat against Everton on December 4 last year. Having failed to shine in his four prior starts, the Belgian had a good game against Crystal Palace. He missed a sitter in the first half, but other than that, he put in a good display, winning back possession more than any player on the pitch and passing the ball around well.
Still, having barely played for months, it is likely that Fellaini won't be used from the start in United's second game in four days, with Darren Fletcher a good option to play alongside Michael Carrick.
Adnan Januzaj had a good game for United on the left, with Moyes opting to play three attacking players behind Robin van Persie, but it is unlikely he will start again in Greece.
If Moyes is to stick with the 4-2-3-1 he played at Palace, chances are that Antonio Valencia or Ashley Young will be brought in to replace the Belgian youngster. Moyes seems to believe they have more to offer defensively and will want to ensure United come away for the second leg in the strongest position possible.
Van Persie will lead the attack like usual with Wayne Rooney playing behind him. Juan Mata's absence could lead to a rare appearance for Shinji Kagawa. Which side Kagawa plays on will likely depend on whether Moyes goes for the left-sided Young or the right-sided Valencia.
Van Persie has eight goals in his last 10 league games, whilst only Luis Suarez, Daniel Sturridge and Sergio Aguero have more goals and assists than Rooney this season. Rooney also has more assists than any player in the Champions League this season, which is a tally he will certainly be keen to add to.