HOUSTON -- Once Johnny Cueto figures out how to economize his pitches and smooth the rough edges, the quality of his performances for the Reds will consistently elevate to the quality of his stuff.

Until then, there will be nights like Thursday's 8-6 Reds loss to the Astros, in what was Cueto's rookie season finale.

Matched up against Houston starter Roy Oswalt, who improved to 23-1 lifetime vs. Cincinnati, Cueto already had his work cut out for him before he stepped on the mound. It proved to be an early night, as he gave up five earned runs and seven hits over 2 2/3 innings, walking three and striking out one. He left trailing, 5-1.

Finishing 9-14 with a 4.81 ERA and 158 strikeouts in 174 innings, Cueto didn't have a great season. It can't be considered a lousy one either.

"It was a season of learning for him," Reds manager Dusty Baker said. "He threw the ball very well sometimes. He made some mistakes sometimes that cost him a few games. He had a lot of strikeouts. He gave up quite a few home runs. He's going to be very good."

Against Houston, Cueto faced 19 batters and threw 75 pitches in that brief amount of time.

In the Astros' second with one out, shortstop Jeff Keppinger bobbled a potential double-play ball on the ground by Brad Ausmus and had to settle for one out. Oswalt followed with a single to right field. After Kaz Matsui's walk loaded the bases, Michael Bourn hit a three-run double to left field and made it a 3-0 game.

"That second-inning double play would have erased a whole lot of pitches," Baker said.

In the third inning, Cueto hit Geoff Blum with a 1-2 pitch and with two outs, Ty Wiggington singled to center field and Ausmus sent the bases full with an infield hit stopped up the middle by Keppinger's diving play. Oswalt blooped an RBI single to right field, and Cueto was finished when he walked a run in against Matsui.

"Oswalt hurt us pitching and hitting tonight," Baker said.

Oswalt (17-10) gave up one run and two hits over six innings with three walks and three strikeouts. In the top of the first, Corey Patterson hit a 2-0 pitch to the deepest part of the park in center field for a homer. Oswalt retired 11 of the next 13 batters.

The Reds sent nine to the plate and tightened the game with a five-run ninth inning that included Jerry Hairston Jr.'s three-run home run. With the tying run at the plate, Astros closer Jose Valverde had to finish the game for the save.

With a reputation that already preceded him, Cueto paralyzed hitters throughout Spring Training and easily won a rotation spot. His Major League debut on April 3 vs. Arizona was electric, as he gave up just one run and one hit with 10 strikeouts over seven innings for a win.

Although there were pockets of solid outings since, Cueto lacked consistency -- an often typical issue for a 22-year-old rookie who was still in Class A ball when last season started.

"The big key for me is to work ahead of hitters," said Cueto, with bullpen coach Juan Lopez interpreting. "At the beginning of the year, I was having success. In the second half, they made adjustments and were kind of tough. I started learning about the hitters that made adjustments on me. I tried to make adjustments. It was a big learning process for me."

Cueto led National League rookies in strikeouts and was among leaders in starts, innings pitched and wins. His 14 losses are the most for a Reds rookie since Chris Reitsma lost 15 games in 2001.

"To me, he is ahead of where Edinson Volquez was when he was a rookie with Texas," Baker said. "It's the big leagues. Johnny is a competitor and works hard. He's going to be a big winner."

Cueto will return home to the Dominican Republic this winter believing the possibilities are endless for him.

"I was fine, but I know I need to get better," Cueto said. "I have the stuff to be one of the tough pitchers in this league."