Mr Patil said what surprised him was that prior to elections in Karnataka, he had visited the state and people there appeared "satisfied" with the Congress government.
The BJP on Tuesday emerged as the single largest party but fell nine seats short of a majority in Karnataka, where the Congress dramatically backed third-placed rival JD(S) for a post-poll alliance to keep BJP out of power.
Elections were held for 222 seats on May 12 while polling for the remaining two will be held later.
The BJP bagged 104 seats, a gain of 64, while the Congress notched 78, a loss of 44 seats, though its vote share was nearly two percentage points more than the BJP.
The JD(S) secured 37 seats, down by three from its previous tally.
Reacting to the poll results, Mr Patil said he had visited Karnataka during the election period and "all was well with the Congress government".
"Even the common man and farmers were satisfied with the government. The Congress was doing well there," he claimed while talking to reporters in Thane last night.
"But it is really a surprise to see such an outcome," he said.
Justifying his demand for the use of paper ballots in polls, Mr Patil wondered why the Election Commission or EC can't revert to the old practice when such a system was prevalent even in some developed countries.
The EC should not insist on EVMs for conducting polls, he asserted.
"If the BJP is insisting for the same, then it is better not to hold elections at all," Mr Patil stated.
On his party's plan to tie-up with the Congress in future polls, he said, "Presently, the BJP wave has receded and hence, the NCP and the Congress have come together to contest elections."
Notably, the Congress has decided to tie up with the Sharad Pawar-led NCP for the bypolls to two Lok Sabha seats in Maharashtra, scheduled on May 28.
While the NCP will contest the Bhandara-Gondia seat, the Congress will fight the Palghar seat.
Mr Patil exuded confidence that Congress nominee Damodar Shingda will win the Palghar Lok Sabha bypoll.
The by-elections were necessitated due to the resignation of sitting BJP MP Nana Patole in Bhandara-Gondia and the death of Palghar's sitting BJP member Chintaman Wanga.