MIDWEEK match-winner Bolo Zenden has warned Middlesbrough team-mate Stewart Downing that he will become a marked man if he continues to produce the kind of dominant displays that put Lazio to the sword on Thursday.

Zenden scored twice as Boro beat their UEFA Cup opponents 2-0 to open up a three-point gap at the top of Group E but, with both goals coming from Downing crosses, the Dutch international still found himself somewhat overshadowed by his colleague.

With Sven Goran Eriksson due to announce his England squad for the forthcoming friendly with Spain next weekend, Downing's performance led to inevitable calls for him to be included in the party that will travel to Madrid.

Zenden is understandably delighted with the 20-year-old's progress this season but, after emerging in similarly explosive fashion himself more than ten years ago, the midfielder sounded a note of caution ahead of tomorrow's Premiership clash with Bolton.

Sam Allardyce was an interested onlooker at the Riverside on Thursday and, with Downing no longer Boro's best-kept secret, the Trotters boss is sure to have plans in place to deal with the wing wizard.

"You start off as an unknown but, when you make a bit of impact, that doesn't last for too long," said Zenden, who scored from the spot as Middlesbrough beat Bolton in last season's Carling Cup final.

"Our opponents will start to focus on Stewart as well now and it will be a test to see how he copes with that.

"It will put some more pressure and difficulties onto him.

"We've got a rough diamond on our hands, but we don't want to spoil it and make it go wrong.

"It's up to the manager to deal with it, and I think that goes for all of the players who are doing really well at the moment.

"The youngsters are showing what they are capable of, and Stewart is probably the one that is furthest forward of them all.

"He'd already played a few games at the start of the season, and he made a great impact of the end of last year.

"It's great to have him there to do his job, and you just hope that he can stay calm with all of the hype that is coming his way."

Zenden is no stranger to that hype as he was still a fresh-faced teenager when he was fast-tracked into the PSV Eindhoven side in the early 1990s.

Playing in Downing's left-wing position, the former Chelsea star made an immediate impression and quickly became the darling of the club's fans. But, whereas Downing is on the verge of being fast-tracked into the England squad, Zenden waited much longer for international recognition.

Previous England bosses have not been afraid to give youth a chance - Michael Owen was still a teenager when he was blooded amidst the intensity of a World Cup finals - but, with the current national side crying out for a natural left-footer, Zenden hopes Downing's promotion is not out of necessity.

"In Holland you have to perform for a year and prove yourself in the Dutch league before you get a chance for the national team," said the 28-year-old.

"I had to earn my spot in the PSV team and then go on to earn my spot in the national team as well.

"It seems to be a little bit different here. When I was growing up, people were saying 'He's doing well at the minute but let's stay calm and not rush things'.

"But everybody reacts differently. I dealt with things quite well when I broke through and, as senior players, we have to make sure Stewart does the same."

At the start of the season, Downing's emergence looked like putting pressure on Zenden as the duo tussled for Boro's left-wing berth.

But, with Ray Palour having been shuffled to the right flank to replace the injured Gaizka Mendieta, Zenden has been able to move inside to great effect.

Three goals in less than a week have underlined the threat he poses from central midfield, while his partnership with compatriot George Boateng already looks like being mutually beneficial to both parties.

"I've known George for a long time because we came through the ranks together in the youth and national teams," said Zenden.

"When I used to play on the left at PSV, he was playing right back for Feyenoord so we ran into each other a lot.

"We've got a very good understanding. George and Ray are the engines in midfield - they make the whole thing work and provide a link between front and back. It's helped me to be playing alongside players like that."