The easy part is over for Roger Federer. The US Open is about to get a lot harder for the Swiss master.
The 16-times grand slam champion is through to the quarter-finals and in majestic form, but most of his main rivals are too. Only Andy Murray has made an early exit.
Federer booked his place in the last eight with a 6-3 7-6 6-3 win over Jurgen Melzer at the Arthur Ashe Stadium on Monday without ever having to play at his best.
It will take a mighty performance from his rivals to stop him capturing a sixth title at Flushing Meadows but there are willing challengers ahead.
His next opponent is Robin Soderling, the big-hitting Swede who ended Federer's French Open defence earlier in the season.
If he gets through that, Federer could then face Serbia's Novak Djokovic, who beat him in the semi-finals at the Australian Open in 2008.
There is also Rafa Nadal, as always, lurking on the other side of the draw if they both reach the final. Federer may be the greatest player of all time but nothing is ever assured.
Soderling and Djokovic also moved through to the quarter-finals yesterday, the former overcoming Albert Montanes, one of six Spaniards who made the last 16 of the men's draw, 4-6 6-3 6-2 6-3.
It was a workmanlike performance but Djokovic was all class and looks the more threatening. The world No3 demolished the improving American Mardy Fish 6-3 6-4 6-1 and is steadily building momentum and confidence.
Meanwhile, Caroline Wozniacki cleared one of the major hurdles in her bid to win the women's title when she eased past an error-prone Maria Sharapova, who is still battling to regain her best form after struggling with injuries for the past two seasons.
Sharapova was soundly beaten 6-3 6-4 but contributed to her own downfall with 36 unforced errors and nine double faults, including three in successive points.
She was one of two former U.S. Open champions from Russia that were beaten in straight sets.
Svetlana Kuznetsova also departed, losing 7-5 7-6 to diminutive Slovakian Dominika Cibulkova.