Dubai - Stan Wawrinka reached his second final of the season as Nick Kyrgios retired injured from their semi-final at the ATP Dubai Championships on Friday.
The Australian quit due to back pain while trailing 6-4, 3-0, having had on-court treatment after the seventh game of the opening set.
"I was never going to be able to really make too much of an impact in the match with the way I was serving," Kyrgios said. "I've been feeling so bad every day.
"I seem to have some kind of viral infection. I couldn't really serve anywhere near my full capacity and he was playing great anyway.
"It was a bit of a struggle, to be honest."
Wawrinka now moves into position for a possible second trophy of the season after winning in Chennai to start the year.
The French Open champion will face either sixth seed Feliciano Lopez, who advanced in the quarter-finals when Novak Djokovic was unable to continue due to an eye infections, or former Australian Open finalist Marcos Baghdatis.
Wawrinka, ranked fourth, carries an enviable record into the Saturday title match at the Aviation Club, having won his last eight finals.
Kyrgios ran out of puff after winning his first career ATP title last week in Marseille and travelling directly to the Gulf; his win streak of nine consecutive matches was ended by Wawrinka in 44 minutes.
"He wasn't really there from the beginning, wasn't serving his best," Wawrinka said. "But you never know what to expect, with him.
"I was focused on myself. I wasn't expecting anything. I was trying to play my game, to stay tough, stay there, trying to win every point and that's it.
"I'm in the finals so there is one more match to play my best tennis, that's the most important.
"If you look from the beginning of the week I was not playing great at all. But I was trying to find a way.
"I'm happy I improved this week, not playing some great tennis, frustrated during matches but still fighting and trying to find solutions to win more matches to play better.
"I started to feel better on court already yesterday. I'm moving better, I'm a little bit more relaxed and my strokes are going better."
Kyrgios now faces a race against time to be fit for next weekend's Davis Cup first-round tie against the United States in Melbourne.
There was no sign of any hard feelings between the outspoken Kyrgios and Wawrinka as they played for the first time since the Australian insulted the Swiss's girlfriend during a heated match last August in Montreal.
"The tension was there because it's a semi-final and I don't want to lose. I want to win," Wawrinka said.
"I want to play better tennis. I want to be in the final and have a chance to get the trophy.
"That's why I get the tension. But the rest, there wasn't, from my side, anything special."
Wawrinka, playing in Dubai for the first time in eight years and without a win prior to this week, went up a double break on Kyrgios in the opening set but lost it.
The 30-year-old Swiss earned his third break for a 5-4 lead and served out the set in the next game.
Kyrgios's level dropped in the second set, with the 20-year-old ranked 33rd giving up after losing three straight games.