By Julien Pretot NEW YORK, Sept 8 (Reuters) Expectations were so high for Venus Williams that the seven-time grand slam champion choked in her U.S. Open semi-final against fellow American Sloane Stephens on Thursday, according to former world number one Mats Wilander. The 37-year-old Williams reached two major finals this season but Stephens denied her a third in a 6-1 0-6 7-5 victory on Arthur Ashe Stadium. "Venus looked a little bit nervous, she looked a little bit nervous in the Wimbledon final too, which is understandable at 37 years old because you're not going to have many more chances," Wilander, in Flushing Meadows as an analyst for Eurosport, said in his daily chat with Reuters. The Swede said Stephens's playing style had everything to bother the ninth seed, who grew more frustrated as the match went on. "The match-up is bad for her because Stephens gets everything back in play, she's so fast and shots that usually are winners for her, she has to hit again and hit again and it's not really Venus's strength," said Wilander. "She likes to hit a couple or three shots and then the rally is over." That was rarely the case against Stephens, whose defence eventually made the difference, with Williams missing several volleys. "Today she was forced to come to the net and you can tell she's not that natural to come and finish off points but it was a great effort to come back after losing the first set," Wilander said. If Williams had won, it would have been the first time since 2002 that she had played in three grand slam finals in a year, but Wilander said it was obvious her passion for the game was still at sky-high levels. "She was in three finals in 2002, she could have done it 15 years later. Her passion for tennis is just through the roof. It's Roger Federer level," said Wilander. "She should have won the match but she's had so much success in her career and when you keep pushing the envelope and keep playing, things turn around and you're not going to have the same success at some point." REUTERS AKC0804