Boris Becker believes that Roger Federer is 'disrespecting' his opponents with his new service return tactic.
The world number two has recently adopted the approach of moving forward as far as to the service line to return on his opponent's second serve, taking the serve on the half-volley.
This charge-and-chip tactic has paid dividends for the Swiss, and was effective in his straight-sets victory over Richard Gasquet in Wednesday's US Open quarter-final. However, it is not a tactic that has gone down well with Becker, who believes that players from his era would punish Federer by serving straight at his body.
"If he would have played a [John] McEnroe, [Jimmy] Connors, [Ivan] Lendl or even me, we would have said 'Roger, in all honesty I like you very much [but] I'll go straight at you'," Becker, who coaches world number one Novak Djokovic, told Sky Sports.
"In my generation guys would not have accepted as it is now.
"It's almost disrespecting the other guy's serve. Everybody talks about that's his new strategy – he comes in. It's within the rules."
Federer recently explained that the approach, which has been dubbed the SABR (Sneak Attack By Roger), came about after a dare from one of his coaches, Severin Luthi.
“At the end of practice we were just kidding around almost. I said, ‘Okay, I’m going to chip and charge and just keep the points short. I’m tired. I want to get off the court soon anyway.’ That’s when I started to run in and hit returns. I hit a couple for a winner. They were ridiculous,” explained Federer.
“He laughed, I laughed, Severin laughed. Then I did it again in the next practice just to see if it actually would still work again. Then I tried it the next practice and it still worked.
“That’s when Severin said, ‘Well, what about using it in a match?’ I was like, ‘Really?’
“So he pushed me to keep using it and not shy away from using it in big moments.”