Manchester United, minus many of its stars, has begun training for its North American tour with a 59-minute session at the Chicago Fire's home ground before about 1,500 fans in 90 degrees Fahrenheit (32 degrees Celsius) heat. The Red Devils open their four-match trip in Toronto Friday against Scottish Premier League side Celtic. After two matches against Major League Soccer sides, it concludes in Houston on July 28 with a match against the MLS All-Stars. “That will probably be our toughest game,” United manager Alex Ferguson said. “It's probably a bigger game for MLS than it is for us. I think you'll find they'll be well motivated because of that. We're used to the fact teams always want to play well against us.” It's Manchester United's third preseason trip to North America since Ferguson became manager in 1986. “Each time I see an improvement in American soccer,” Ferguson said. “The MLS has proven itself now. The performance of the (US) national team helps. They were very credible in their performance in the World Cup, and I think that helped the younger people in the States. “We know there are millions of kids playing. The MLS has to structure itself so these kids can eventually get to MLS. It'll take time to build a pyramid of soccer so they get to the MLS.” Manchester United was without World Cup participants Wayne Rooney, Patrice Evra, Michael Carrick, Nemanja Vidic and Park Ji-sung at training Wednesday. They get 30 days rest before they're required to begin their next season. Manchester United's English Premier League season begins Aug. 16, when it hosts Newcastle. The training session, the first on-field event of United's trip, was held in the southwest suburbs of Chicago because the team's new corporate sponsor, AON, is headquartered downtown. Bolton blanks Charlotte Martin Petrov made an immediate impact in his Bolton debut by scoring a goal and setting up another in the Premier League side's 3-0 preseason win over the Charlotte Eagles Wednesday. Gary Cahill and Johan Elmander also scored in the first match of Bolton's three-game North American tour. Bulgarian Petrov, the former Manchester City midfielder, sent a short corner to the near post which Cahill headed into the net in the eighth minute. Elmander scored in the 50th minute and Petrov made it 3-0 with his strike to the upper left corner from 25 yards out in the 80th minute. World Cup players Stuart Holden, Danny Shittu and Lee Chung-yong didn't make the trip.
