Chelsea’s win over 1-0 Tottenham was soured by a ‘worrying’ injury to defender Thiago Silva.
Silva has been excellent for Chelsea since making the move from Paris Saint Germain.
He has marshalled the Blues’ defence superbly, but he was forced off after 36 minutes of the 1-0 win over Spurs in the Premier League on Thursday.
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Silva stretched to make a clearance, and remained on the ground in pain.
He received treatment, but was ushered off the pitch to be replaced by Andreas Christensen.
"I saw Thiago with a big strap around his muscle but we have to wait,” Tuchel said. “It's worrying because it's a muscle injury."
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Tuchel was pleased with the win, but wants to see his players show a killer instinct in front of goal.
“Every experience we make is a step forward if we are open to learn from it,” Tuchel told BT Sport. “There are many ways in football to have a good performance.
We want a bit more killer instinct, and a bit more aggression in the box, as it would have been nice to decide the game earlier.
“There were chances when we lacked a bit of determination in the box. But it is good to have things to improve and it is a big win in an away game.”