England star Theo Walcott insists he and his Arsenal team-mates must be “on our game” when they face Premier League newcomers Norwich City tomorrow.

The Gunners come to Carrow Road for the day’s early kick-off (12.45pm) looking for a fifth successive league victory after recovering from a disastrous start to the season to move into seventh spot in the top-flight, two places above the Canaries.

But with three defeats already on the road, the 22-year-old Walcott knows they face another testing afternoon against Paul Lambert’s team, who gave Chelsea and Manchester United a run for their money on their own territory and took a point at Liverpool – and now have home advantage against one of the division’s big guns.

He said City’s promising start to life back in the Premier League had not come as a shock.

“I’m not surprised by their start at all,” he told Arsenal.com. “All the teams who come up tend to do well at the start of the season.

“They show tremendous spirit because they’ve got nothing to lose at times. Obviously they will be the underdogs going into the game but we can’t take that for granted.

“It will be a tough game and they are playing well – especially at home at this moment in time. We have to be ready and on our game.”

Walcott was just 16 when he first appeared at Carrow Road in a Championship fixture back in December 2005 as part of a Southampton team beaten 3-1 by a Dean Ashton hat-trick. A month later, he joined Arsenal for �5m, a fee that eventually rose to �9.1m.

He has contributed four goals so far this season, but the Gunners have relied most heavily on the Premier League’s leading scorer, Robin van Persie, who has scored eight times in the last four league games and 11 in all.

With City conceding six goals in the last two matches, it remains to be seen whether Lambert makes any defensive changes tomorrow.

He was today expected to give an update on the fitness of the two casualties from the 3-2 defeat at Aston Villa a fortnight ago, when midfielder Bradley Johnson was taken off in the first half with concussion and defender Russell Martin suffered an ankle knock that forced him to withdraw from the Scotland squad for the friendly in Cyprus.

Lambert has been without three central defenders for most of the season, with Zak Whitbread (hamstring) and Daniel Ayala (knee) injured since August and Elliott Ward (knee) yet to make an appearance.

He must also decide whether to persevere with two strikers after playing both Steve Morison and Grant Holt at Villa Park, or revert to one front man as in the previous six games.

Gunners boss Arsene Wenger must also decide whether to make changes and keep some of his big names fresh for Wednesday’s Champions League game at home to Borussia Dortmund.

A sell-out crowd and live TV coverage will heighten the profile of City’s first real glamour home game since promotion, but the bigger the occasion, the better they have performed under Lambert.

The Canaries will be looking for their first home win over the Gunners since 1984, and their first home or away since the 4-2 success on the opening day of the first Premier League season in 1992.