New Oxford United boss Matt Bloomfield was given an early indication of the size of the task he faces as he saw his side narrowly avoid an FA Cup upset at the hands of League Two MK Dons.

With the new head coach watching from the stands as interim boss Craig Short took charge for the final time, the Championship side struggled for long periods against their lower-ranked opponents only to squeeze through in a penalty shoot-out.

Aaron Collins' smart finish from close range 11 minutes before the interval gave the home side a deserved lead and, but for a good save from visiting goalkeeper Matt Ingram he may have doubled that advantage.

Will Lankshear swept home Oxford's equaliser early in the second period but, after Ingram and Dons goalkeeper Craig MacGillivray both pulled off decent stops to keep the tie level, Jonathan Leko and Connor Lemonheigh-Evans missed their kicks in the shootout to edge the U's into round four.

With Oxford making six changes from the side beaten at Ipswich on New Year's Day, they quickly found themselves on the back foot at Stadium MK as the home side sensed an upset, forcing Ingram into saves from a Scott Hogan header and a Ben Wiles strike.

The U's were dealt a further blow when debutant Jamie Donley was forced off with an injury after 17 minutes, to be replaced by another new signing, Myles Peart-Harris.

Ingram was finally beaten when, from a well-worked corner, Jack Sanders' header was helped on by Lemonheigh-Evans and Collins found the back of the net from close range.

It could have been worse for the visitors but for Ingram throwing out an arm to make a superb reflex save from Collins three minutes before the break, and the overworked goalkeeper was called into action almost immediately after the restart as Aaron Nemane ran half the length of the pitch only to see his shot tipped around the post.

Oxford had been so lacking as an attacking force it always seemed likely it would take a set-piece to get them back in the tie and when a Will Vaulks long throw was allowed to bounce through to Lankshear he gratefully turned in his seventh goal of the season.

Despite that setback, MK Dons continued to create chances with Ingram saving from Collins and Sanders before home goalkeeper MacGillivray did well to tip over substitute Oli Romeny's late effort.

Brian De Keersmaecker and Peart-Harris were both denied by MacGillivray in extra time but with neither side able to find a winning goal it came down to a penalty shootout.

Leko hammered his spot-kick over the bar to give Oxford the advantage and with Romeny, Mark Harris, Peart-Harris and Matt Phillips all scoring, it was perhaps fitting that Ingram had the final say by saving from Lemonheigh-Evans to send the U's through to round four for the first time in six seasons.

MK Dons boss Paul Warne told BBC Three Counties Radio:

"The overall performance I really liked.

"I thought we had the better of the chances, we defended a lot of crosses but unfortunately we got done by a long throw and they scored.

"Generally over the course of the game there wasn't a lot in it and that's probably the best compliment I can give my players because at times you wouldn't know which team was which.

"The positive thing is if this team was able to get promoted, that was more like a League One game tonight than a League Two game, and you can see we have players who can definitely compete at that level."

Oxford United's interim head coach Craig Short told BBC Radio Oxford:

"It wasn't pretty at times - I was getting frustrated in the first half because we were forcing it.

"The lads stuck at it - today was just about getting through. I know MK are in League Two but they're a good side and I was pleased with that.

"I met Matt (Bloomfield) for the first time when he came into the dressing room at the end and spoke to the lads.

"I don't know if he wants me. I understand when new managers come in they want their own staff, it's a ruthless business and you want people around who you can trust.

"I think he knows I don't want the job, I'll make that clear to him anyway and if I can be of any help to him then I certainly will."