Venus Williams beaten by Swiss teenager Celine Naef in first match since January hamstring injury

WATCH: Venus Williams Seen Preparing For Grass-Court Comeback | The Break

DEN BOSCH, Netherlands (AP) — Seven-time major champion Venus Williams lost her first competitive singles match since injuring her hamstring in January, succumbing to 17-year-old Celine Naef 3-6, 7-6 (3), 6-2 at the Libema Open grass-court tournament on Tuesday.

With family members including her sister, Serena, in the stands, the 42-year-old Williams battled temperatures around 30 degrees Celsius (86 degrees Fahrenheit) and an opponent making her WTA debut to win the first set before losing a second-set tiebreaker and wilting in the decider.

"Amazing. I cannot believe I had the chance to play against Venus," the Swiss teenager said on court after her victory. "She's an amazing player and really a role model for everyone."

Williams, now ranked No. 696, was put under pressure by Naef in the seventh game of the first set but served strongly to save two break points and take a 4-3 lead. Williams then broke Naef to love to take a 5-3 and served a love game as she reeled off 12 straight points.

Wimbledon, the British grass-court major which Williams has won five times, opens on July 3. Williams' last singles major title was at Wimbledon in 2008.

Williams injured her hamstring in January in Auckland. She broke first in the second set but Naef fought back to force the tiebreaker and dominated the deciding set.