Former USA vice-captain Timroy Allen and fast bowler David Pieters were the standout players during Sunday's trial matches at the ICC Americas Combine in Indianapolis. Allen top-scored in the first T20 trial match, which was played on the main turf wicket at the Indianapolis World Sports Park, before following it up with a fiery opening spell as his team defended a total of 102 to win by six runs.

"In every trial scenario, they're always going to look at techniques and all that but on the other hand you have the match situation and the position you have been put in. You have to do whatever it takes to get your team through," Allen said.

Allen also spoke highly of the talent at the trial and was impressed with the level of competition on display. "There's a lot of potential here. For there to be these many guys here, and the amount of cuts they're making, there's going to be a lot of potential that get bypassed."

Pieters, who hails from San Diego, was the leading wicket-taker in the opening match with 3 for 15 in his four overs and also executed a run-out in the field. He gave credit, particularly, to being able to work with Courtney Walsh on Saturday during the skills assessment rotations.

"That was amazing. I've never experienced anything like that. Just being in that personal space with him and having him actually challenge you. He wasn't an easy coach. He wasn't taking it easy on us at all. He wanted to push and get the best out of us and that's exactly what he did. Just the way I ended with that session yesterday, hitting the cones that he wanted me to hit and getting a clap from him, I couldn't have asked for anything better."

The 66 players will have another day of trial matches on Monday before final selections are made for phase two beginning on Friday.

Peter Della Penna is ESPNcricinfo's USA correspondent. @PeterDellaPenna