Valencia withstood a late onslaught from Real Betis to move up to second with an enthralling 6-3 win at the Benito Villamarin on Sunday.
With David Villa transferred to Atletico Madrid, Tello will likely share time on the attacking left flank with Brazil striker Neymar under newly appointed coach Gerardo Martino.
Roura also made a special mention of the contribution made by the Barca fans as more than 85,000 turned up for their first midday kick-off at the Camp Nou in nearly 50 years.
Adrian Colunga temporarily interrupted the one way traffic with an effort that floated over the bar, but Barca were soon back on the front foot and Messi should have had his second of the afternoon when he turned Sanchez's pin-point cross onto the post.
Liverpool manager Brendan Rodgers revealed on Thursday that he hopes to seal two more signings in the next 48 hours.