DODGERS NOTEBOOK: FATHER'S ILLNESS WEIGHS HEAVILY ON RELIEVER OSUNA.

Byline: Matt McHale Daily News Staff Writer

Antonio Osuna pitched the ninth inning Sunday in the Dodgers' 10-5 victory over the Pittsburgh Pirates at Three Rivers Stadium, but his heart was still in Mexico.

Osuna returned to the club Sunday after spending four days with his father Alberto, who has been diagnosed with throat cancer. Osuna's mother Antonia, has had a recurrence of heart problems that forced her son to leave the Dodgers last season.

``It has been a very difficult time,'' Osuna said, after allowing a run in the ninth. ``I know the team needs me, but these people need me, too. There was so much sadness there. When I was on the mound, it was hard to focus.''

Osuna learned 10 days ago that his father was sick. A biopsy was done Friday on throat tissue, which came back malignant. Osuna, who lost his closer's job to Scott Radinsky after a slow start, did not throw during his absence. He worked out before the game and spoke to manager Bill Russell and executive vice president Fred Claire about his situation.

``He's an important part of this team,'' Russell said. ``Hopefully, he can regain his focus soon. It's a very difficult time for him. We wanted him to know we are there for him.''

Osuna pitched one inning and allowed one run.``I wasn't very good, and I need to be,'' he said. ``It will be better next time. Those people in Mexico count on me to support. I can't afford to let them down.''

Unlucky Lankford: Reliever Frank Lankford made his first appearance since giving up a game-winning single to Milwaukee's Jeromy Burnitz last Monday. After taking over for injured Chan Ho Park, Lankford, who gave up a three-run homer to the Cardinals' Mark McGwire in the second game of the season, pitched three innings and allowed a three-run homer to Kevin Young in the eighth.

``Same pitch I made to McGwire and to Burnitz, a hanging breaking ball,'' Lankford said. ``I'm sure I made that pitch to others, but those are the most memorable. It is one of my best pitches, but I don't have a lot of confidence in it right now.''

Streak continues: Pirates outfielder Mark Smith extended his season-opening hitless streak to 29 at-bats when he pinch hit and grounded out in the fifth. That ties him with former Dodger Jose Gonzalez, who did the same in 1991 and the Angels' Mick Kelleher in 1982.