Xabi studied what made them stumble at the start of the season and now they are back to their best form and that has brought them back to 2nd place behind Bayern Munich by just 4 points.
There is still a long way to go, the key is for them to be consistent and their meeting with Bayern Munich could be a very decisive meeting for their position. In the last few meetings, Leverkusen have had very satisfying results, including the first leg which ended in a draw. A draw is already a good result, although a win would certainly be a very good result.
I also still believe that Leverkusen's chances are still very big as long as they are consistent like they are now and the key to all of this is that Alonso must retain some players without selling his important players. And in the transfer market later when it reopens, Alonso should at least bring in more qualified reserve players.
Because the schedule will be even tighter when they have to compete in the Bundesliga and UCL. So Leverkusen needs second-tier players who have almost the same performance as the main players.
Leverkusen's strong consistency is currently a big threat to Munich and the Bundesliga is now very interesting because the Bundesliga giants are no longer easy to win the title.