The fourth position isn't the problem anymore but the 5th position because UEFA has added one more slot to make it five clubs qualifying from EPL to the Champions League next season. It's only if United wins Europa League that only the top four clubs on the table at the end of the season will qualify to UCL. Let's see amongst these three teams which of team wouldn't make it to UCL next season.
Newcastle, Chelsea and Manchester City will continue to try to be better in the rest of the season in order to get that place because all three really want to be in the Champions League next season. Moreover, with the addition of one place in the English League to become a participant in the Champions League next season, it has increased the enthusiasm of the English League teams, especially for the three of them, in making their appearance even better until the end of the season arrives.