The versatile defender scored a stunning 25-yard effort in the first half to settle the match at London Road.
The Honduran has been used sparingly during pre-season due to a slight groin strain but Agnew believes he can have a big contribution at the KC Stadium.
"He's so athletic, he's strong, he's quick and he strikes a good ball," he told the club's official website.
"He's had a groin problem at the back end of last season. He's had 60 minutes today, we'll build him up slowly."
After a 2-1 loss to Birmingham City on Saturday Agnew was pleased with the way the team responded.
"Our pressing and our work out of position was better," he continued. "We got to the ball quicker and gave the opposition less time to play.
"Our use of the ball could be better. We need to continue on possession and retaining the ball for longer spells for three weeks.
"We're three weeks into a six week pre-season programme, so far so good.
"We put more crosses in, put more players into the box, one or two chances which just which just went across bodies. We made more chances it was pleasing."
