Neil Harris admitted it will be difficult for Millwall to secure a Wembley outing after the Lions were beaten 2-0 by Oxford United in the first leg of the Johnstone’s Paint Trophy southern area final.

League Two Oxford, who have lost just one of their last 17 games in all competitions, secured a two-goal lead at half-time through a Kemar Roofe brace.

Despite spells of pressure after the break, the Lions were unable to find a breakthrough and will have to overturn a heavy deficit at the Kassam Stadium in the second leg to book their place at Wembley.

“We had enough chances to win two or three games tonight. We have given ourselves a mountain to climb but we're capable,” Harris said.

“We’ve had 19 efforts on goal and not scored. Our goalkeeper [David Forde] has made a bad error, he’s put his hands up, no problem.

“The ball bounced around their box all evening but never fell to us. If you don’t take chances you don’t win games.”

The Lions almost took the lead after just ten minutes at the Den, but striker Steve Morison failed to hit the target with a close-range header.

Five minutes later Roofe’s innocuous cross somehow beat David Forde at the near-post to provide Oxford with the lead.

Gregory had an opportunity to draw level after bursting into the box, but the forward’s attempted lob was wayward.

Oxford doubled their lead on the stroke of half-time - John Lundstram’s long-range effort struck the bar and fell to Roofe who nodded home.

Millwall new-boy Jed Wallace, making his home debut, looked certain to half the deficit after the break, only for Benjamin Buchel to make a superb stop.

Morison and Chris Maguire both wasted good opportunities at opposite ends of the pitch, before Morison’s deflected shot was well saved by the impressive Buchel.

Late pressure from the hosts proved futile as high-flying Oxford moved one step closer to a place at Wembley.

Harris said: “I thought some of our play was really good, although we were a bit direct.

“We got in so many good positions but the final ball into the box and the finishing wasn’t quite at the standard that we expect and are used to.

“It’s frustrating because Oxford had some nice passages of play, but we had most of the territory and the chances but we’re sitting here disappointed with a defeat.”

The Millwall boss acknowledged that his side face an uphill battle in the second leg in Oxford.

“It will be tough, we’ve given ourselves a mountain to climb,” he said. “But the belief will be in there, for sure.

“The next goal certainly makes or breaks the tie.”