Boris Becker has called out Roger Federer's new SABR tactic as "almost disrespecting" his opponents, ahead of a potential US Open final against his charger Novak Djokovic.
Federer unveiled his latest weapon at the Western and Southern Open in Cincinnati against Djokovic, and has continued to use it at Flushing Meadows with great success.
The two remain on track to meet in the New York decider ahead of Friday's semi-finals, but Becker made his view clear - if he was still playing, he would serve straight at Federer's 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 said on Sky Sports.
You might also be interested in:
"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."
Djokovic takes on defending champion Marin Cilic in the first semi on Friday night on Arthur Ashe Stadium, followed by Federer's all-Swiss battle with Stan Wawrinka.