Maybe Chelsea doesn't have a big enough chance to take 5th place from Tottenham because the Premier League doesn't have many matches left. Apart from that, even though Tottenham Hotspur is in poor performance, Newcastle could be an obstacle because they have also been playing quite well recently.
Tottenham is quite safely at their fifth position and Chelsea now looks similar to Liverpool last season. Rising performances of Liverpool in latest weeks of last season were not enough for them to get a fourth position from Newcastle United. This season Chelsea are facing with a same disappointed fact but they firstly must feel happy with their recent performances. They are improving a lot recently and are harvesting their training, efforts with good results lately.
Tottenham's performance has not been that good recently; they are no longer performing the same way as they were at the beginning of the season, and Chelsea have shown some consistency recently. I think Chelsea are fighting to end the season at the top 4 in the table, and with all indications, I think they can continue performing this way. I believe they will do it, though I can’t guarantee Chelsea a win against Tottenham because Tottenham are also not a team to underestimate, and they won't want Chelsea to take over, so let's wait and see what Chelsea will do at the end of the season, since they have been improving. Let's see if they are going to continue this way till the end of the season.