Talk about rubbing salt in a wound.

Hedgie David Einhorn on Wednesday had to endure Twitter taunts from Tesla founder Elon Musk — one day after telling investors in his Greenlight Capital fund that they were down a woeful 18.3 percent through the first half of the year.

The 49-year-old investor and the stressed-out carmaker have been at odds since Greenlight shorted Tesla a couple of years ago.

After announcing Greenlight’s tough first half, Einhorn told investors in a letter that he is “happy” his Tesla Model S lease was ending.

“There were growing problems with the touch screen and power windows,” Einhorn noted. He then added a second zinger: He is excited to soon be getting a Jaguar I-PACE, the first electric model from the luxury carmaker.

As if that wasn’t enough, Einhorn then got personal — calling the 47-year-old Musk “erratic and desperate.”

That was enough to get Musk tweeting.

“Tragic. Will send Einhorn a box of short shorts to comfort him through this difficult time,” Musk tweeted early Wednesday.

Einhorn may indeed be angry about his Tesla lease — but he could also be a bit twisted that Tesla shares, despite production problems, gained 29 percent in the second quarter.

It was Greenlight’s second-worst-performing investment.

Stay tuned. Tesla reports earnings Wednesday after markets close.