(Reuters) - Twice French Open champion Serena Williams said her struggle to beat Sara Errani in the Fed Cup on Sunday had been a real "eye-opener" as the claycourt season gets into full swing.
World number one Williams eventually prevailed 4-6 7-6(3) 6-3 against the dogged Italian to take her career record over her to 8-0 but the American was not impressed.
The U.S. were beaten 3-2 as Williams and Alison Riske were thrashed 6-0 6-3 in the doubles rubber by Errani and Flavia Pennetta, meaning they were relegated to World Group II.
"Today has been a big eye opener," Williams said afterwards.