England captain Eoin Morgan said he had no regrets despite a four-wicket defeat that denied his team a one-day series whitewash against Pakistan.
Spinner Liam Dawson, selected with Adil Rashid and Moeen Ali rested, took 2-70 from eight overs, the most expensive figures by an England debutant.
"It was an opportunity to get him on the international stage," said Morgan.
"It was important looking ahead to the winter in case we go to three spinners that he had a game under his belt."
England's winter tours take them to Bangladesh and India, where conditions are likely favour slow bowlers.
|Most expensive ODI debut figures for England|
|DV Lawrence||11-1-67-4||West Indies||Lord's||1991|
In Cardiff, they were denied a first 5-0 home ODI series win as Pakistan chased down 302-9 with 10 balls to spare.
Sarfraz Ahmed made 90 and Shoaib Malik 77 in a stand of 163 that rescued the tourists from 77-3.
England had earlier failed to build on a strong position of 170-4 from 30 overs, losing five wickets for 64 runs and managing only 42 from their final eight overs.
"Today, we just weren't good enough," Morgan told BBC Sport. "We were a little bit off and Pakistan played really well on a very good wicket.
"It's not a big defeat for us. We still played well. We weren't good enough to score maybe 350, which is a shame. We've played some fantastic cricket throughout this series with some notable performances."
'A win here and there won't help'
For Pakistan, avoiding a whitewash brought them only a second win in 14 ODIs against England.
Captain Azhar Ali told BBC Sport: "It's a win which we really needed, to finish on a high. It's been a tough tour, especially in ODIs, but finishing like this at least gives us a lot of confidence and the players happiness.
"We didn't bowl well to start with, we were a bit too short but credit to the bowlers for the way they came back.
"Chasing 300 on that kind of wicket was a challenge against a good bowling attack so it was a very good effort from Shoaib Malik and Sarfraz. The partnership they had set us up very nicely.
"We just need to play some consistent cricket, fearless cricket. You have to back yourself as a batsman, fielder or bowler. We need to do that consistently, that's the only way forward. A win here and there won't help if we don't play good cricket consistently.
"At the end it got nervy a little bit but (Mohammad) Rizwan kept his head and Imad (Wasim) is a very mature guy who really handled the situation well."
Pakistan's tour, and England's home summer, concludes with a Twenty20 match at Old Trafford on Wednesday.