Return long back/side spin serve on backhand

I struggle a lot with long underspin serves placed into my backhand corner, or into my crossover point. They usually have left sidespin too. I try a small backhand loop, but then the ball usually goes into the net. If I try a straight return, it goes wide on my left side. I struggle to lift the ball.

The feeling is that the ball approaches very quickly, there is not enough time. I might stand too close too, but I think it is the reaction time.

Just putting the ball on the table usually gives a too high return and puts me immediately under pressure. I think my best chance is to attack.

How can I better prepare for those returns? 

Hi Martin,

Working on the topspin return is the best way to progress.

You could try taking a half step away from the table.  However, you may be able to improve your reaction time by watching the ball carefully on the tops of your opponent.  The other thing is to be a little lower with your legs.  This will help you to get under the ball and lift it with the topspin.  Make the stroke more vertical as well to help to lift the ball over the net.