I also thought as much over several year now Tottenham has been playing in the Europa League and without winning is it that the problem is from coach or players. Because it has reach that they suppose have doing something better by now, since the last time they won their only playing every season and at the end of day they will end up of losing.
The problem is from the coaches that they had over the years and their management. But in this case I will stress more on the coach. Why I said is the coach is that it's been same similar crop of players that Tottenham Hotspur has had over the past 5 years and nothing happened. But when Postcogulu came in, he let everyone know that he usually win something in his second year in his club. He built that mentality in his players and they delivered something in his second year. So if the previous coaches had set a standard that they wanted to win something, they would have won.