Zaheer, 28, won selection in India's 15-player squad for the forthcoming tournament starting in West Indies next month after he made a strong comeback to regain his old role as pace spearhead.
He has bowled impressively since he was recalled for the South Africa series late last year, to make amends after enduring the lowest point in his career in 2003.
A nervous Zaheer bowled a 10-ball first over costing 15 runs in the last World Cup final against Australia at the Wanderers, after skipper Saurav Ganguly chose to bowl first. India were overwhelmed by 125 by the defending champions.
Zaheer was heavily criticised after being chosen to bowl the first over ahead of the experienced Javagal Srinath.
His India future looked in serious doubt after he was axed in February last year due to a slump in form and fitness in a test series defeat in Pakistan. Local media also linked the sacking to his attitude problems and differences with coach Greg Chappell.
However, Zaheer fought his way back with fine performances for English county Worcestershire, taking 78 wickets in 16 games.
He bowled consistently well in South Africa on his return and grabbed 11 wickets, including his first five-wicket haul in ODIs, against Sri Lanka to help the hosts complete back-to-back series victories against West Indies and the islanders.
"It (the county stint) helped me grow as a cricketer," Zaheer said. "You play six days a week and my bowling fitness improved a lot.
"I have been able to hit the length consistently because I have bowled so many overs."
The Mumbai bowler's 172 wickets from 117 one-dayers makes him the most experienced seamer in the team after Ajit Agarkar, who has 272 scalps from 180 appearances.
Skipper Rahul Dravid has called Zaheer the key to India's World Cup hopes, praising the bowler who has trimmed his final leap before delivery without compromising on pace or control.
With youngsters Shanthakumaran Sreesanth and Munaf Patel to back up -- both figured in India's first test series win in West Indies for 35 years in 2006 -- Zaheer looks set to get the new ball again.
This time, he plans to get it right.
With inputs from Agencies