on a roll: 连连获胜

美网大赛前的重要热身赛--辛辛那提大师赛决赛结束，世界球王费德勒毫无悬念的连续第六次击败老对手罗迪克，摘得本赛季个人的第四个大师系列赛冠军，同时将2005年的总战绩提升到64胜3负。本场决赛之前，费德勒在决赛中已经保持了21连胜，同样对罗迪克也保持了五连胜。外电报道如下：

When Roger Federer reaches a tournament final, he doesn't lose. Nobody knows that better than Andy Roddick. The unflappable Federer won his 22nd straight final on Sunday, beating the exasperated¹ American 6-3, 7-5 for the Cincinnati Masters championship and his ninth overall² title this season.

Federer improved to 10-1 against Roddick, who tried every tactic³ but still came up short. Federer has won the last six times they've met, including the last two Wimbledon finals. The world's top-ranked player for the last 81 weeks, Federer heads into the U.S. Open fit, relaxed and on a roll. He took time off after winning his third straight Wimbledon, looking to recharge and rest a sore foot.

文中的on a roll表示"连连获胜中；连续交好运中"。If someone is on a roll, they are successful or lucky for a short period of time. 例如：When he won one game after another, it was obvious he was on a roll.（当他赢得一场又一场比赛时，很明显他正在连续交好运。）