LONDON, July 5 : Jannik Sinner has struggled in searing heat in the previous two Grand Slams this year, but the Italian said he was well prepared to handle it in southwest London, with temperatures expected to soar at Wimbledon this week.After a heatwave last week, which broke British records for June at around 37 degrees Celsius (98 degrees Fahrenheit), the second week of the tournament is forecast to see temperatures climb again beyond 30 degrees Celsius.Sinner, who hails from the Alpine region of South Tyrol in northern Italy, struggled physically during a Paris heatwave to fall in the second round of the French Open in May and suffered cramps in an early scare at the Australian Open in January.The four-times major winner will take on German Jan-Lennard Struff in the quarter-finals but