Chelsea manager Frank Lampard believes his side must improve if they are to seal a Champions League spot.
The Blues earned a nervy 1-0 win over Norwich City in the Premier League.
They now have two league games remaining against Liverpool and Wolverhampton Wanderers.
Four points from those two games would be enough for Chelsea to keep matters in their own hands.
Asked about the top four race, Lampard told Sky Sports: "It's a tough one to call. We know our fixtures are hard, but everyone else also has tough games. This is the Premier League and it's not easy.
"We take our three points, we focus on ourselves, we can sit down and watch the other teams this week and focus on our FA Cup semi-final at the weekend [against Manchester United], but there's obviously still work to do.
"There's a nervy feeling for understandable reasons, so I'm pleased. We went a bit slow for about 10 or 15 minutes in the second half. Then we began moving the ball again and there was a bit of personality in our game today, but we can improve."
