The return of Justin Harrison to bolster a lineout that faltered in the midweek win over Munster is one of five changes Matt Williams has made to his starting line-up ahead of the meeting with Glasgow at Ravenhill tomorrow.

Williams today admitted that the set-piece let his men down against the European cup finalists and put it down to a "bad night" but has seen fit demote Ryan Caldwell to the  bench as his side look to copper fasten their position as Ireland's third seed in next year's Heineken Cup.

Justin Fitzpatrick is another who gets the nod ahead of Bryan Young in the frontrow and Neil Best replaces Kieron Dawson at openside flanker.

Number eight Stephen Ferris is replaced by Roger Wilson after picking up an injury against Munster and a fractured cheekbone for Bryn Cunningham has seen him replaced by Mark Bartholomeusz, with Scottish international Simon Danielli coming in on the left wing.

"They are a side who have improved enormously throughout the last season. They play an open and attractive style of rugby and I know some of the players well so I am looking forward to this fixture," Williams said of his opponents today. "With the week we have had, the game against Glasgow is a huge challenge.

"We had a technically bad night, nobody is hiding from the criticism, there is no excuse. So far this season our line out has been solid and after Wednesday night the only thing the players can do is get back on the pitch and get it right again."

Ulster's 19-9 win over Munster was part one of a three-part challenge completed but Glasgow offer a fresh test in what is gruelling period due end with another tough test against second-placed Cardiff Blues in their final fixture.

"Training has gone well this week, clearly the fixtures and scheduling isn't perfect but I have had no complaints from the players, they know they just have to get on with it," said Williams.

"The boys showed real pride on Wednesday night in their defence and tomorrow will be no different, it will be another hard 80 minutes and mentally it is all about the heart and playing for the shirt"

Ulster: M Bartholomeusz; T Bowe, A Trimble, R Dewey, S Danielli; P Wallace, I Boss; J Fitzpatrick, R Best, T Court, C Del Fava, J Harrison, M McCullough, N Best, R Wilson

Replacements: N Brady, B Young, R Caldwell, K Dawson, K Campbell, N O'Connor, M McCrea