Lamela looked bad. No one looked good, but he did nothing.
First time I've watched Tottenham this year. Lamela seems pretty confused, even more so than the beginning of last season at Roma when Zeman alluded to him and Nicolas Lopez as a couple of chickens with their heads cut off.
Doesn't seem like the experimental nature of the Tottenham's attack is doing him any favors though. It seemed that Lamela played about 4-5 different positions over the course of the match.
He's going to need a LOT of coaching as his problem at Roma was similar. He just seemed to not really understand what he should be doing in the team framework and therefore tended to "drift out" of matches.
It's not surprising that he ultimately did pretty well under Zeman since that radically open attack meant Lamela was constantly in tons of situations where the defense was outnumbered and his job was very clear.
I'd guess Tottenham fans will need to be patient with him as he's certainly a work in progress that's mainly been hyped more off immense potential than production so far.