How to avoid OTB chess cheating in time pressure?

Recently I played in the last round of a 10 5 OTB tournament. Both down to the last minute and playing white I had a mating attack when my opponent played Rxf3, my Queen was on h4. He checked my King on h2 with Qb2+. I covered with Rg2. Then surprisingly he took Qxg2+ white played Kxg2 then his black rook appared illegally placed on f4 not f3 and the following move captured my queen on h4 winning a whole rook! I wasn't aware of the trick. After the game people around told me what occurred but my opponent replied that it was an accident accomodating the piece even though he's a young U-18 experienced player nationwide. I finally managed to draw the game thanks to a passed pawn and finished 5th place instead of 2nd. I'm over 40 and I'm not very active in OTB chess. I'm used to clean sportmanship in chess but nowadays cheating is everywhere. Any comments about avoiding these nasty little tricks in time pressure?  

yeah watch the board

You're old and rusty.This shit will happen to you regularly.Sorry.

If it's FIDE, the arbiter should have noticed.

Some people write down the moves when there's a 5 second delay.

The big thing is to be aware of what's going on, stop the clocks and get a TD over there immediately.

I used to play golf and watched high schoolers drop balls by the green for their teammates who played a hole behind them. Cheating is everywhere. In some games it's actually encouraged! (Diplomacy board game).

It is unfortunate, but alas this is the nature of human behavior. It's actually part of what makes our species so successful. I'm sorry you got taken advantage of, and I think your best defense was as SmyslovFan said. I abhor cheaters, but they're not going away anytime soon.

In Diplomacy and Mah Jongg, it's not cheating if it's not caught. Those games are considered to be based a bit more on "real world" ethics. Diplomacy is Kissinger's favorite board game!

In OTB blitz games when I rush to calculate a knight path sometimes I accidentally move it 2 squares in a straight line. If it wasn't intentional I wouldn't think of it as cheating. It is very embarrassing to not notice an illegal move though. I've had this happen to me too. At first I was really mad at my opponent, then a day or two later after I calmed down I realized it was probably an accident on his part.