Yorkshire left-arm fast bowler David Lucas virtually guaranteed that his contract will be extended to the end of the season by capturing 6-20 on his first team debut against Leeds-Bradford Universities at Headingley yesterday.

And Australian paceman Adam Warren, who is having trials with Yorkshire, also impressed director of cricket David Byas by grabbing two wickets with his first seven deliveries for the county as the Universities began their slide to 105 all out.

But Yorkshire did not have everything their own way on a day in which 23 wickets crashed in helpful swing conditions and they were bowled out for 151, the Universities then closing their second innings on 12-3 when they trailed by 34 runs.

Lucas, 26, was signed from Nottinghamshire during the close season on a three-month contract, which is due to be reviewed at the end of June, and Byas admitted that he had been pleased by his performance and that of Warren.

"They both put the ball in the right areas and were well rewarded for their efforts," he said.

Lucas added: "The ball was a bit slippery at the start of my spell but it was swinging quite a lot in the humid conditions and that helped me.

"I was delighted to take six wickets but I think I have been bowling well all season for the Second XI.

"I think I have been bowling well enough to deserve an extension to my contract but I will just have to wait and see.

"Whatever the outcome, I have really enjoyed myself at Yorkshire and I am very grateful for all the help I have received from bowling coach Steve Oldham, who has been fantastic."

Warren, who plays for Bootle in the Lancashire Premier Competition, said: "It was great to get two wickets with my first seven balls and this helped to relax me, although I am 29 now and not overly nervous."

Leeds-Bradford opening batsmen Adam Patel, who plays for Cleckheaton, and Gharib Nawaz, who is with Saltaire, set off at a cracking pace against Chris Silverwood and John Blain with 44 coming off the first nine overs before Warren came on and had Patel caught behind.

The second ball of his next over trapped Nawaz lbw offering no stroke and when Lucas came on the batting disintegrated completely. Lucas also struck with his fifth ball, Jos Siddall presenting Simon Guy with the second of his three catches.

None of Yorkshire's main batsmen really stood out against a youthful and enthusiastic attack, the most successful bowlers being Tom Glover and Danny Jones, who each took three wickets.

But Yorkshire's 46 lead was more than useful and the chances of the students making a big recovery were dashed as the wickets continued to topple in their second innings.

Updated: 11:12 Friday, June 03, 2005