Manchester united have also been playing well in the premier league, just the same way Barcelona have been playing well in the La Liga, Manchester united are also in the carabao cup final, while Barcelona are in the copa del rey semi final, so the both clubs are playing very well recently, and it becomes hard to predict who will win. From my own perspective, the game is very open for the two clubs and any of them can win, maybe home advantage can help Barcelona to win the game tonight, or maybe it can end as a draw, and everything will be decided in the second leg.
After leading 1-0 thanks to an Alonso header, then Barcelona had to concede Rashford's goal and Kounde's own goal due to chaos in front of goal. This was a lucky goal for Manchester United through Rashford's acceleration left by Ter Steigen. It's great for Manchester United, but I believe Barcelona is still possible to win this match in the end.
There is still time to make the difference even though Manchester United's attack is very dangerous. I feel optimistic about this and shouldn't be guilty about what I expected. 20 minutes of normal time must be put to good use by Barcelona, but they must also be prepared enough to stem Manchester United's attacks. Without Pedri I think Barcelona lost control in the middle, he is an important player who can organize attacks well.