Defending champion Mardy Fish and John Isner lined up a re-run of last year\'s final at the ATP Atlanta Championships with decisive semi-final victories. Top seed Fish on Saturday won his eighth straight match at the venue as he schooled American teenager Ryan Harrison 6-2, 6-4 in a win over a promising youngster a decade his junior. Isner, seeded third, will play his second final in as many tournaments after beating Luxmbourg\'s Gilles Muller 7-5, 6-7 (3/7), 6-1. Fish beat Isner in the final a year ago in a third-set tiebreaker played in heatwave conditions. Weather on Sunday promises to be around 30 degrees Celsius (86 Fahrenheit) and slightly more tolerable. \"I had to play well and I did play well,\" said Fish, whose number nine ranking makes him the highest-ranked American on the ATP tour. \"This was the best I\'ve felt on court. It was my toughest match of the week against my most difficult opponent.\" Isner is riding high on confidence after breaking a lean spell with a second career title, lifted a fortnight ago on grass at Newport. \"I always play my best when I\'m confident,\" he said. \"I can move better when I\'m confident. I\'m not the fastest guy, but I\'ve been moving well this week. \"It comes from having a clear mind and making the right decisions on the court. Now that I feel like this, I don\'t want to let it go.\" Isner used his huge serve to advantage in a victory achieved in just under two and a half hours. The American rained down 28 aces to 16 for Muller, who was playing in his first semi-final since Los Angeles six years ago. Isner was playing back-to-back ATP semi-finals for the first time in his career. Fish admitted that his serve let him down on court \"but everything else worked fine.\" The final will be his first day match of the week after a run of night sessions. \"The balls will be a bit quick,\" Fish predicted. \"With John the points are usually short. \"But he makes you work on service games. It will be physical, but it\'s great to be back in this position.\" Fish holds a 2-1 career record over Isner and will be trying to defend a title for the first time in his career after playing his fourth semi of the season. He has come back strong after losing both singles rubbers in a Davis Cup loss this month to Spain while coping with the effects of a lingering abdominal muscle strain.