The three-time world champion lamented a rusty opening during which he fell 3-1 behind, but was pleased with how he rallied for a 9-6 victory.
Selby will face the winner of Shaun Murphy and Mark Allen in the last four, where he will be intent on sharpening up.
"To be fair, the first four frames before the interval, pathetic really," said Selby.
"But then after that I felt as though I got into the match, tried to pick up the momentum and find some tempo.
"And I felt as though from three-one to win the match nine-six, I didn't really do too much wrong.
"Yes, I missed a few balls, but I think we're going to.
"We've not played that many matches for a while. So it's understandable, but from three-one I felt as though I played okay.
"And I'm happy enough with my performance from three-one, if you cancel out the first four frames."
Selby conceded he was fortunate to clinch the 12th frame in a "cruel" and ultimately decisive blow to Bingtao.
"The balls were going against me and Yan did well to get back in the frame," said Selby.
"But nobody deserves to lose a frame like that, it's a cruel way to lose it after he fought so long to get back into it."
Selby can at least point to breaks of 99, 105 and 119 as he searches for top form.
Asked if toughing out a victory is the best route back to full sharpness, he said: "Well I hope so. I've been practising hard for the last week and a half, two weeks, but it counts for nothing.
"A lot of the time you're practising on your own, you feel you're playing okay but then you go into a match like that and you can get caught out because you've not had any match practice.
"So it is difficult to know where your game's at."