The arrival of Argentine winger Angel Di Maria from Real Madrid for a British-record 59.7 million pounds (USD 99 million) took their spending this transfer window to over 130 million pounds but as Van Gaal knows, splashing the cash is no guarantee of success.
The experienced Dutchman has yet to register a competitive victory, picking up one point from two league games and suffering an embarrassing 4-0 League Cup thrashing at third-tier MK Dons on Tuesday.
United's name was missing from the Champions League draw after last season's seventh-place finish, compounding the gloom around Old Trafford and although Van Gaal insists it will take time for the squad to adjust to his methods, rapid improvement is required at Turf Moor.
"Our problem is when we have the ball," Van Gaal said.
"We have to build up the play and we have to improve that. So I don't think our defence is weak - no, our build-up is still not good enough and we shall improve that, but that needs time,” he added.
United are missing Michael Carrick, Shinji Kagawa and Luke Shaw through injury while Marcos Rojo is still unavailable as he has yet to receive a work permit.
Burnley manager Sean Dyche, without a point from matches against Chelsea and Swansea City, said it was important not to get caught up in the interest surrounding Di Maria, who is expected to play.
"They have made a lot of changes and a lot of the attention will be on them this weekend. That's no disrespect to ourselves because there is an outside view of us being written off by the bookies, etc," said Dyche, who has spent less than five million pounds on strengthening his squad for life in the top flight.
"Clubs being talked about in higher regard than our own is something we will get used to over the season, not for vicious reasons,” he added.
Romelu Lukaku and Samuel Eto'o could appear against former club Chelsea when the sides clash at Goodison Park on Saturday.
Everton manager Roberto Martinez will make a late decision on 33-year-old Eto'o's involvement but he expects Lukaku to play despite a sore toe.
"Rom has strong inner strength and I don't think he is motivated by who he is facing or who is in front of him," Martinez told the club website.
Winger Christian Atsu is not eligible to play against his parent club.
Chelsea are chasing their fifth successive away league victory as they bid to continue their unbeaten start to the new campaign.
Also on Saturday, champions Manchester City host Stoke, Queens Park Rangers face Sunderland, West Bromwich Albion travel to Swansea, West Ham United entertain Southampton and new Crystal Palace manager Neil Warnock takes his team to Newcastle United.
Tottenham Hotspur have made a steady start under new boss Mauricio Pochettino, and will hope to banish the memories of two heavy defeats by Liverpool last season when they host the Merseysiders on Sunday.
Liverpool tore Spurs to shreds, winning the matches by a combined 9-0 but under Pochettino they are yet to concede in the league.
"The past is the past. I don't want to remember the past. It is a new season,” Pochettino told reporters.
The Reds have been boosted by the purchase of controversial Italian striker Mario Balotelli from AC Milan and being drawn with Real Madrid in the Champions League group stage.
They will be keen to get back to winning ways after losing 3-1 at Manchester City, the side that pipped them to last season's league title.
Aston Villa host Hull City and Arsenal travel to Leicester City in Sunday's other matches.

Latest News from Sports News Desk