Andy Murray's losing streak on the ATP Tour stretched to three matches as he suffered a first-round exit to Tomas Machac at the Open 13.
The three-time major champion was sent packing in 97 minutes during his maiden clash with Machac, who triumphed 7-5 6-4 to set up a second-round meeting with Lorenzo Musetti.
Despite beating away Machac's first two break points, Murray succumbed on the Czech's third opportunity as he lost serve in the third game of the match, although he showed some fight to draw level at 3-3.
However, the 36-year-old - who won the Open 13 in 2008 - lost serve once again in the 11th game as Machac edged a tight opener, and lightning then struck twice for the Briton, who was broken in his second service game of the second set.
Murray only fashioned one chance to break back against the world number 66, but he squandered that opening and exited with a whimper, as Machac held to love to extend the 36-year-old's dismal run.
While there was disappointment for Murray, another former British number one - Heather Watson - sprung a surprise at the Abu Dhabi Open, eliminating ninth seed Veronika Kudermetova.
The 31-year-old had to come through qualifying to set up a first-round showdown with the world number 16, who replaced Jelena Ostapenko in the draw after the Latvian withdrew from the tournament.
Both players boasted one win over the other heading into their Abu Dhabi opener, but despite the 140-place chasm in the WTA rankings, Watson dominated and deservedly prevailed 6-3 7-5 in one hour and 43 minutes.
The world number 156 raced into a 3-0 lead before Kudermetova earned one break back, but the Russian could not back up the break and immediately lost serve again, winning just one point behind her second serve in the entirety of the first set.
Neither woman gave much away in the second set, although Kudermetova squandered a 40-15 lead in Watson's second service game, and another crucial break arrived for the Briton in the 11th.
Two match points came and went for Watson, but the third time was the charm for the former British number one, who will battle Spanish lucky loser Cristina Bucsa in round two before a potential quarter-final meeting with top seed Elena Rybakina.
Earlier in the day, Harriet Dart emulated Watson at the Transylvania Open, following up a pair of qualifying wins with a straight-sets success over Hungary's Anna Bondar.
The 27-year-old had suffered defeat in her maiden WTA Tour meeting with Bondar in Cluj two years ago, but despite recording five double faults on Tuesday, she prevailed 6-4 7-6[0] in exactly 100 minutes.
Dart was broken first in the sixth game of the opening set, but the Briton's setback only galvanised her as she won four on the trot to turn the first set around, and her dogged showing also saw her save two match points at 4-5 in the second set.
Dart's powers of recovery had sucked the life out of Bondar, who was blown away in the tie-breaker, and the British number three will meet either Elisabetta Cocciaretto or Emiliana Arango in round two.
